London Weather

How severe can the frost be?

2012-01-31T12:31:00.000-08:00

There is much talk at the moment about severe frosts affecting this area over the coming nights. So how severe can severe be? Last night ice formed on the pond as the temperature dipped to minus 3, and ice will probably stay on the pond for several more days. If the ground remains frozen that helps nights to become colder, and a deep snow cover helps even more. Since 1991 the lowest February temperature has been minus 6.0, this being recorded in both 2007 and 2008. The lowest temperature of any month recorded at this site was minus 9.9 on the morning of February 10th 1991 over 17cm of fresh snow. Prior to that, the temperatue was almost as low in the February of 1986. The coldest Februaries overall since 1900 didn't necessarily produce the lowest minima, mainly because strong winds and cloudy skies prevailed. In 1947 a minimum of minus 9.7 occurred but the lowest seems to be minus 11.8 in February 1895. Is it there to be beaten?

There is still time!

2012-01-25T03:53:00.000-08:00

The crab apples are beginning to rot on the trees and so far there has been no sign of the Redwings or Fieldfares that descend on the tree when there is 'real' winter weather. There still hasn't been any 'proper' snow and the days are steadily lengthening. The forecast charts occasionally hint at a blast from the east but without much conviction, although there is still hope. Some of the coldest Februaries have been proceeded by average, or even mild, Januaries. In 1947, the coldest February since 1900, was preceded by fairly mild weather up until mid January. In 1986, the second coldest February since 1900, the preceding December was less snowy than December 2011! There were just 2 days with a few blobs of sleet. January 1986 was a wet month with temperatures close to average. Sleet or snow fell on 8 days but it didn't settle. The last week of January became rather cold and winds swung to the northeast and then February! The first few days of the month were dull and drizzly although a little snow settled on the evening of the 2nd. Real winter began on the evening of the 5th. Snow fell followed by a frost, and snow then remained on the ground until the 5th March with every night during that period having a frost. Time will tell!

Frosty nights, but not exactly winter!

2012-01-17T06:31:00.000-08:00

There have been 4 consecutive frosty nights, and the pond has been frozen solid for 4 days, but it's hardly wintery weather. There were 3 days of 'snow' during December, although the 'snow' was. in fact, sleet with a limited amount of snow flakes, so it won't be a winter free of snow. However, it's beginning to look as this month could be devoid of snow. The last January without snow was in 2002, but snow-free Januaries are not that unusual. In 1989, 1990 and 1992 January was free of snow here, but according to Brazell, London Weather (1968), 'a January without at least local snow (in the London area) is rare and there have only been 5 years since 1900. The Januaries in question were 1904,1906,1916,1925 and 1944. By way of contrast, there were 21 days with sleet or snow falling in January 1963 and the ground remained snow covered throughout the month. A January without an air frost is extremely rare. In 2008 there was only 1 air frost in Morden, but it appears that the only January without an air frost in the Morden area was 1938.

Soft January days

2012-01-10T04:27:00.000-08:00

At the moment, with a third of the month gone, this January is the mildest since before 1900. It hasn't been wall to wall sunshine, but the soft grey clouds with chinks of blue showing through are nevertheless uplifting when accompanied by a temperature that frequently tops 10 Celsius. Since 1900, a total of 4 out of the top 10 mildest Januaries have occurred during the last 10 years and only 2 of the mildest Januaries occurred before 1974. The mildest January, 2007, had maxima above 10 Celsius continuously from the 3rd to the 20th, and on 6 days the high topped 13 Celsius, a figure we haven't reached this January. The highest value was 14.2 Celsius on the 18th, a day of destructive winds when a gust of 58 knots (64 mph) was recorded here. Although the month was record-breakingly mild, it was not without its wintery moments. Sleet or snow fell on 5 days towards the end of the month and on the 24th there were 3 centimetres of snow carpeting the garden for most of the morning.

A very mild Christmas

2011-12-26T04:42:00.000-08:00

At this time last year we were just emerging from our biggest December freeze for 120 years. Snow lay on the ground. albeit in the form of large icy patches, and after a maximum temperature of just minus 0.9 Celsius on Christmas Day, Boxing Day dawned with a low of minus 6.8 Celsius. This December, mild, but unremarkably so, has not seen temperatures anywhere the values recorded last year. Yesterday (Christmas Day) was the mildest in this area for 13 years, and today, with the temperature nudging 13 Celsius, is also the mildest Boxing Day since 1998. Last year, the temperature failed to rise above 10 Celsius during the whole of December, but for snow lovers the rest of the winter was a dismall failure. A few flakes of snow were observed in the rain on 3 days during January and no snow fell in February. So what of the rest of the winter of 1998/1999? Apart from a brief snowy spell at the beginning of the second week of February, southwesterly winds prevailed bringing plenty of mild changeable weather; and this winter?........

No snow......yet!

2011-12-11T04:57:00.000-08:00

The Christmas trees are all lined up ready for the festivities, but this year it's looking as if the Christmas period will be green, as it usually is of course! On this day last year the temperature reached 8 Celsius, but it was also the first day of the month with no snow observed in the garden. The snow returned on the 16th, and although it was not a 'true' white Christmas with snow falling, there was enough of the white stuff around to produce a supply of icy snowballs. A white Christmas with snow falling is much rarer than a December without snow falling. There has been some snow falling in the last 3 Decembers, but prior to that 4 out of 6 Decembers were completely free of snow. Also, the definition of 'snow' to the meteorologist is any preciptation that contains snow flakes whether partially melted on not. So, a cold and wet day with the odd blob of very wet snow is registered as a 'day with snow' . It remains to be seen if this December gets it's day of snow, but in the last 40 years there have been 16 snow-free Decembers in this area. The odds of seeing snow this month are good.....but not very good!

Second Best

2011-12-04T03:46:00.000-08:00

The frost has left the banana looking sad but all the talk is about the warmth of November, the autumn and the year. In this area, November 2011 was the 2nd mildest since before 1900, the autumn (September, October and November) was also the second warmest since 1900. Currently the year 2011 is also the 2nd warmest since 1900! So, what does December need to make it number one. The year to beat is 2006. January and February were actually milder this year than in 2006 by about 1.5 degrees. The spring was much warmer this year by about 3 degrees. However, the summer was much cooler by almost 4 degrees. This autumn was less than a degree cooler than the autumn of 2006; so where does that leave the last month of the year. December 2006 was mild with a mean temperature of 7.7 Celsius. In fact, that made it the 5th mildest December since 1900. For 2011 to be the warmest year since 1900 this month needs to have a mean temperature of 8.6 Celsius. In December 1974 the mean temperature was 8.7 Celsius so the figure is achievable, but this year? No, pretty unlikely, second best again!

Another mild and sunny day

2011-11-27T05:02:00.000-08:00

November 2010 was a fairly dry month, but that is the only weather feature it shared with this November. So far this month there have been no air frosts, although tonight could change that statistic. There have been several mild and sunny days, a continuing characteristic of this autumn, and although the leaves have fallen off most of the trees, the run up to winter is very different from last year. On this day in 2010, it was cloudy, not unusual of course, but the maximum temperature was only 1.4 Celsius. That is 12.7 Celsius lower than the highest temperature recorded today. Although a frost is a possibility for tonight, the minimum will undoubtedly be several degrees higher than on the corresponding night last year. On that night the temperature fell to minus 5.9 Celsius, the lowest November reading for 21 years. On the last day of the month there was heavy snow, and the good folk of this area awoke on the 1st of December to an 8 centimetre covering of snow! Not so this year, presumably.

The Fog Myth

2011-11-21T05:02:00.001-08:00

The fog which descended over parts of London and persisted through much of Sunday helped to fuel the myth that London is a foggy city. Certainly the pea-soupers that plagued the Capital in the past justifiably gave the city a bad reputation. The polluted fog of early December 1952 was probably responsible for over 4000 deaths in Greater London and this eventually led to the Clean Air Act of 1956 and a decline in the instances of choking fogs. Nowadays, the heat island of London helps to reduce the number of 'natural' fogs and the few fogs that do occur are usually confined to, or are at their worse in, low-lying suburban areas of London. The statistics for Morden show that since 1988 November, on average, has been the foggiest month. However, a day with fog (defined as a day when visibility is below 1000 metres at 0900 UTC) has only occurred on 19 occasions, and the highest number of foggy days in any month has only been 4. Thus the 'foggy London' tag has well and truly been laid to rest.

What about the frost?

2011-11-14T05:32:00.000-08:00

This autumn, so far, has seen a couple of white grass frosts (in October) but no air frosts have occurred. How unusual is that? At this site records began in 1988 and since then there have only been 2 instances where the autumn months, September, October and November, have been completely free of air frosts. The years in question were 1994 and 1999. In 1994, November was exceptionally mild and currently stands as the mildest November in this area since before 1900. Also the temperature difference to the next mildest (1938) is, in statistical terms, quite substantial. However, at the moment, this November is milder than that of 1994, also by quite a significant margin. Today may help to change that, though, with the maximum temperature struggling to achieve double figures. In both 1994 and 1999 the frost-free period did not extend through the remainder of the year. In 1994 the first frost of the 'winter' occurred on December 15th with the 14th seeing the first frost in 1999.

The Autumn Harvest

2011-11-06T06:42:00.000-08:00

The 25 millimetres of rain that fell on Thursday made it the second wettest day of the year, but fortunately the dry autumn has left the soil very manageable. The potatoes have been lifted and the crop looks good, so many baking potatoes for the next few months. There is a heavy crop of carrots, but they're not particularly large and wireworm has been rather problematical this autumn. A bonus this November has been the lack of air frost, so far. There were some white ground frosts on a couple of mornings during October, but no damaging air frosts have occurred this autumn and this has allowed the second crop of figs to ripen. The wet summer in this area has led to a bumper crop of celeriac and beetroot, and netting has largely managed to keep the abundant Cabbage White butterfly away from the brassicas. So, the autumn harvest is now in, with the prospect of cabbages and sprouts for the winter months ahead.

The splendid weather has to end

2011-10-24T11:57:00.000-07:00

Although no records have been broken, this month will be remembered for many dry, sunny and pleasantly warm days, and of course the exceptional heat at the beginning of October. At the moment it is the driest October since 1978, although rain tonight looks like changing that. October 1978, despite being a dry month, was not particularly sunny, and although days were often warm, nights were sometimes quite chilly. The cool nights have been a feature of recent temperature statistics this October, and that has dragged down the temperature averages. Therefore, it seems unlikely that this month will hold on to it's 5th warmest ranking (since 1900) . However, the 4 mildest Octobers have all occurred during the last 16 years and Edwardian or Georgian London would have been very pleased with this mild, bright and smog-free month!

Receding blue skies

2011-10-16T04:41:00.000-07:00

After the amazingly blue skies of yesterday, the clouds have returned. Mustn't grumble, though. This October continues to be the warmest for at least a 100 years but will it last? Well, maybe! Although there have been some fairly warm days, the nights have been chilly under the starry skies. The first real ground frost of the autumn occurred last night, but although there may be some more chilly nights to come, the forecast charts suggest a much more unsettled and windy second half to the month. It should mean maximum temperatures near, or slightly above average, but with nights generally much milder than average under the cloudy skies. So, probably a top 10 spot as a mild October, but number 1 will be more difficult. The mildest October, 2001, only had a monthly minimum temperature of 4.9 (0.7 so far this month!), and there were just 9 days with minimum temperatures below 10 Celsius!

The worst summer since 1993....really?

2011-08-31T02:45:00.000-07:00

The media have, on recent days, quoted Met Office statistics that suggest this summer has been the poorest since 1993. Undoubtedly, this is true for some parts of the country but for south London it has been the worst summer since 1988 with the summer of 1993 nowhere near as bad. Comparing the two summers we find that in June 1993 the mean temperature was 16.9 C with only 9 days when maxima failed to reach 20 C. There were 5 days with highs above 25 C. Rain fell on 11 days and totalled 42.6 mm. In June 2011 the mean temperature was 15.4 C with 16 days below 20 C and only 3 days above 25 C. Rain fell on 17 days and totalled over 81mm. The July figures are 17.0 and 16.4 C; 10 versus 12 days below 20 C, but 3 against 2 days over 25 C. Rain fell on 16 days in 1993 but only 12 days in 2011. However, the total rainfall was 46 mm in 1993 and 52mm in 2011. With one day to go, August 2011 looks like being a warmer month than August 1993. 16.4 against 17.2. However, the mean maximum temperatures were similar on 21.4 C. In 1993 there were 8 days with maxima below 20 C but there have been 10 this year. There were 3 days with highs above 25 C in 1993 and also in 2011. Rain only fell on 5 days in August 1993 and totalled 30 mm, but August 2011 had 18 rain days totalling 67 mm. It's no contest. In this area the summer of 2011 has been infinitely poorer than that of 1993!

Summer coming to an end

2011-08-21T06:21:00.001-07:00

Like it or not summer is coming to an end, at least meteorologically speaking. The 3 calendar months, June, July and August constitute summer but hopefully there will be plenty more 'summer-like' days to come during the autumn. With 10 days left until the end of the month it looks, assuming that there will be more than 10mm of rain before the 31st, as if this summer will be rated as the poorest since 1988. So how poor was that summer compared to this one. Firstly, in June 1988 there were only 25mm of rain against 82mm this last June. There were only 9 days with rain falling but in June this year there were 17 rain days. However, in June 1988 there were 18 days when the temperature failed to reach 20 C., but this year there were only 16 cool days. In July 1988 there were over 65mm of rain measured compared with 52mm this year. The rain fell on 17 days in 1988 but only on 12 days this year. There were 15 days with maxima below 20C in 1988 but only 10 days this year. August 1988 was not wet, just 29mm recorded but temperatures failed to reach 20C on 9 days. So far this month we have had over 30mm of rain but temperatures have only failed to touch the 20C mark on 3 days. It's still possible that this summer will descend to the level of 1988, but probably not.

Time for Harvest

2011-08-14T04:53:00.000-07:00

It's the time of plenty. What ever the weather has thrown at us in the Spring and Summer, there is usually a happy ending in some form for the farmers and gardeners. In this particular area there is a fine crop of Victoria Plums, although several have rotted on the trees, and the same applies to the apples. The exceptionally dry Spring seems to have had little impact on the fruit and vegetables, but the early summer rains have been more influential. On the positive side, apples, pears and potatos are very large this year. On the negative side, there are plenty of maggots in the apples and many are falling off early. The tomatoes are poor this year, but cucumbers are good. Onions, peppers and chillies are also good, so overall it has probably been a bountiful year. Crab apples are in abundance, so hopefully there will be a return of the Fieldfares this winter. Does it mean another severe winter? One thing for sure, the fruit and vegetables are products of the past weather, and NOT the future weather!

Downhill to Autumn?

2011-08-07T07:12:00.000-07:00

Yesterday, Saturday 6th August, is not a date that rings many bells in the weather fraternity. However, for this little part of south London it is, on average, the warmest day of the year. Okay, so the records only go back 23 years, and it is only warmer than the next warmest day by 0.1 Celsius, but the fact stands. Historically, the early part of August has seen some of the highest temperatures. On August 9th 1911 it was very hot across London, and although some of the maxima on that day were recorded in non-standard conditions, values of 38 were measured at Greenwich, 37 at Isleworth, and 36 at Camden Square, Epsom and South Kensington. However, at Kew, the maximum temperature recorded in a standard Stevenson Screen was only 34.3. Record-breaking heat occurred on the 3rd August 1990, and although only 35.5 was recorded here, there were highs of 36 and 37 in the London area. All these hot days were eclipsed on the 10 August 2003 when this site had a maximum of 36.7 and areas in. and around, London had highs around 37 or 38. This was the hottest day since instrument records began, and on an afternoon when the temperature is failing to reach 20 it seems a far distant memory.

So, how bad is this summer?

2011-07-31T03:45:00.000-07:00

The summer is about two thirds over and there are two schools of thought as to how it is progressing. Some think it is very pleasant with good growing weather. Others think it is cool and wet. Statistics point towards the latter claim....but with reservations! It has been said many times that the manipulation of numbers can often produce the results you want to see and the following figures come with the same caveat. By using a ranking system from 1 to 112, with 1 being the warmest or driest since 1900 and 112 being the coolest or wettest since 1900, comparisons can be made. For example, June and July 1976 were both warm and dry. Using equal weighting, June 1976 produce 1+6=7 and July gave 8+16=24. The total therefore was 31. By way of contrast, the June and July of 1987 were both very poor and produced 86+86=172 for June and 56+92=148 for July, a 2-month total of 320. So far, the numbers for June are 67+94=161 and for July 90+59=149, a total of 310. It can be seen that using basic comparisons of temperature and rainfall, the first 2 months of this summer are up there with the worst of them! Let's hope that August 2011 is less forgettable than the early months of summer.

Wet, but could be wetter!

2011-07-17T04:39:00.000-07:00

As the rain hammers down again, it looks as if the monthly average for July could be exceeded by the end of today. In recent years there have been several quite wet Julys. In 2009 measurable rain fell on 22 days, and in 2007 over 124 mm of rain fell, including the 41mm that was recorded on the 20th. Some of the most intense rainfall of the year can fall in July, and large totals over a very short time period are not that unusual. Kensington had 25 mm of rain in 12 minutes on the 11th July 1927, and on the same day 37 mm fell in 18 minutes at Balham. On the 26th July 1946 there was a fall of 50 mm in 35 minutes at Kew. Some parts of Greater London have had over 100 mm in 24 hours and southeast London appears to be particularly vulnerable to these heavier falls. Over most of London it looks as if 1918 had the wettest July with parts of southeast and east London recording over 200 mm of rain. West London fared better with only 121 mm of rain at Kew, a figure this month is moving towards; but will it reach it?

A touch of optimism for July, maybe!

2011-07-11T02:51:00.000-07:00

The general consensus is that this July has been poor so far. Statistics bear this out, with rainfall (up to the 10th) already 50% of the monthly average and temperatures the lowest for 23 years. The month has a long way to go and changes may occur. In some years they are marked. For example, in 1980, after a cool and wet June, holiday-makers were hoping for a better July. Alas, the first day of the month brought strong northerly winds, persistent rain and drizzle and a high of only 15. At midday in central London the temperature was only 12! A couple of dry and warmer days were then followed by more rain, and on the 8th another very cool, windy and wet day occurred with the 9th little better. No let up in the unsettled weather occurred until after mid month with infrequent sunshine and afternoon temperatures typically between 14 and 17. Finally, a sunny day occurred on the 21st, and although the maximum was only 19, it was the beginning of a spell of summery weather that lasted until the last couple of days of the month. On the 25th the temperature reached 28. Despite the warm end to the month, July 1980 was the coldest since 1922, and in recent years, although poor Julys have occurred, none of them have approached the dire weather experienced during the first 3 weeks of that very forgettable month.

July, the best summer month?

2011-07-03T04:52:00.000-07:00

It can be argued that July is the best month of the year even though many of the high temperature records have occurred in August. Looking at the statistics for Morden, these covering the last 22 years, it would appear that day-time temperatures for July are 0.2 degrees warmer than those for August (23.3 against 23.1). Rainfall is 12mm less in July compared with August (43 against 55), in fact in recent years July averages out as the second driest month of the year behind March. All the summer months, along with May, only have 11 days with significant rainfall (0.2mm or more), but it's the subtleties that make July the best month. It hasn't the same number of very chilly days that can often spoil a June (Only 2 of the last 22 Julys have had maximum temperatures below 16, yet 17 Junes have had chilly days including a high of only 11.8 in 1998). August has had 2 years with maxima of 16, but in most years there is a distinct feel of autumn late in the month as the heat from the sun becomes less apparent. So, that's the argument for July, and today is a perfect example. Light winds, a mix of clouds and sun and a temperature of 24. Unfortunately, by Wednesday we'll be seeing the bad side of July weather!

3 fine days and a thunderstorm

2011-06-26T07:59:00.000-07:00

George the Second (1683-1760) was unique in many ways. Firstly he was the last monarch to be born outside of the United Kingdom, secondly he was the last monarch to lead a British army into battle, and thirdly he was considered to be responsible for the adage that a British Summer was '3 fine days and a thunderstorm.' By co-incidence, a long-standing rainfall series for England and Wales commenced in 1727, the same year that he succeeded his father as king. During his reign he probably became aware of some exceedingly wet summer months. 1736 produced one of the wettest Julys ever known, and the Julys of both 1743 and 1751 were also thoroughly wet. Some wet Augusts occurred in the early 1730s, but perhaps it was the extremely wet August of 1737 that triggered the quote. We may never know, but there is certainly some truth in the saying, and as we enter day 2 of the fine spell (and the warmest day of the year so far!) , we wonder if the hot and humid day tomorrow will be followed by that traditional thunderstorm!

Good for the garden...in moderation!

2011-06-19T04:33:00.000-07:00

Rain is almost a daily occurrence this month, and although it has done wonders for the garden, it is now becoming somewhat excessive. So far, this June has had nearly 66mm of rain making it the wettest this century. It has a long way to go before beating the 137mm that fell in June 1997. Nevertheless, there has almost been twice as much rain as we had in the whole of the Spring (March, April and May). Whilst the fruits are filling out quite nicely, the temperature is on the low side for some crops, especially tomatoes. At the moment it is the coolest June for 20 years, although there is a hint of somewhat warmer weather later in the month. The highest daily average temperature occurred in April with 19.3C. May had 18.6C, and so far this month the average is 19.1C. It would be extremely unusual if this situation was unchanged at the end of the month, and it would be even more unusual, perhaps unique, if the highest temperature (27.2C on the 23rd April) turned out to be the warmest day of the year!

Rain, and more rain

2011-06-12T06:32:00.000-07:00

With the drought stories fading from the news as quickly as they appeared, rain drops continue to fall. Of course, some parts of the country are still in dire need of sustained rainfall, but for this area of south London the drought is well and truly broken. So far this month we have had over 45mm of rain. Already it is the wettest June for 4 years, and the wettest start to June since 2002. In that year 42mm fell in just 1 day (the 5th), and back in June 1973 nearly 45mm fell in Morden in 1 day. Recently, Junes have tended to be dry and there have only been 2 wetter than average June since 2000, Prior to that, there were a couple of exceptionally wet Junes. In 1998 nearly 125mm of rain was recorded, and in the previous June (1997) over 137mmwas measured. Although 1997 possessed the wettest June in living memory, in 1903 over 180mm of rainfall was measured at Kew, all of it falling between the 9th and 20th. At Carshalton over 80mm of rain fell on 10th June 1903. By the way, most of the rest of that Summer, and much of the Autumn, remained cool and wet!

1976 and all that

2011-06-04T05:51:00.000-07:00

The grass is beginning to turn brown quite widely, just as it did during the summer of 1976. If the media were to believed in those hot and dusty days England would never again be a green and pleasant land. Of course, the rain arrived in spades late in August and through September. By the end of autumn, there was little to show for the prolonged dry spell. Aside, that is, for a few dead trees, most of which weren't native to southern England. So, where does it leave 2011? Although, it was the driest Spring this year in living memory and beyond in this area, the winter was fairly wet. Already this year we've had over 50mm more rain than we had in the first 6 months of 1976. Also, the weather patterns showed marked differences between the Springs of 1976 and 2011. As a result temperatures are very different. March 1976 was cooler than March this year with no days exceeding 16 Celsius (5 this year). April 1976 had near normal temperatures compared to the record-breaking warmth this year. By way of contrast, May was fairly warm in 1976 with the temperature exceeding 29 Celsius as early as the 7th. Although this May was reasonably warm there were no hot days. June 1976 was outstandingly warm, and although the maximum temperature today is around 27, a decline into maxima mediocrity seems imminent.

The dry Spring

2011-05-29T05:42:00.000-07:00

Less than 72 hours until the end of Spring. For rainfall purposes it ends at 0900GMT on June 1st. At the moment another 6mm of rain are needed to keep the old 1976 record intact. The thunderstorms on Thursday produced over 8mm of rain and that made it the wettest day since January 17th. There was rain at other times last week, but although fronts brought changes of airmass, amounts of rain were negligible. The 'record' now appears to hinge on the behaviour of a minor wave on a cold front currently to the west of the UK. Computer models suggest that this wave will become quite active as it trundles northeast over southern England tomorrow. At the moment, it looks as if the heaviest rain will occur west and north of London, but in addition to this frontal rain, destabilization ahead of the front tomorrow may lead to showers breaking out, although the near continent seems more at risk from that feature. It certainly looks like being a close run thing before Summer begins ..... with the prospect of further records??

Dry, but getting wetter!

2011-05-23T04:34:00.000-07:00

The 23rd of May, the sun is shining, but rain over the weekend has reduced the Spring deficit and it remains uncertain whether the 'record dry Spring will become a reality. A mere 15mm will now take the 3 month total past that achieved in Spring 1976 but there are only 9 rain days left! Let's have a look at the latest charts. At the moment the radar shows a band of rain over Wales and that's forecast to weaken considerably as it moves southeast. Probably 1mm at most before it clears. Tomorrow (24th). Only an outside chance of a shower. 25th suggests a weak front late in the day or overnight, again less than 1mm. So, 6 days to go and 13mm. 26th will probably be showery, typically 2-5mm, with a ridge of high pressure helping to produce a dry day on the 27th. The 28th could well be a wet day 5-10mm, possibly more! Back to showers and around 2mm on the 29th followed by more substantial rain on the 30th (5-10mm) and then showers again on the 31st (about 2mm). Best estimate would suggest the record will be missed by close on 3mm. Bad news for the thrill-seeking statisticians. Great news for the gardeners!

Now it's seriously dry.

2011-05-16T03:57:00.000-07:00

A few spots of rain fell this morning but now it's beginning to look very dry. The trees are losing their Spring lustre and the grass is turning increasingly brown. It's not surprising really. The total rainfall for this area since 1st March (66 days) is only 21.6 mm. To put that figure into context, the 20-year average fall for those 66 days in this area is 105mm, so the total this year is only just over 20% of the average. What of the rest of Spring? Will it beat the record? Interestingly, the average rainfall for the first 15 days of May is 15mm, but for the last 16 days of May the average is 29mm. Therefore, if 'average' rainfall occurs for the last 16 days of the month the record will not be broken! The total for the Spring would then be around 51mm which would rank this Spring as the 6th driest since 1900. However, if only 18mm of rain falls the record will be broken. In 4 of the last 20 years, and 21 of the last 110 years, there have been daily falls of over 20mm in this area during May. So, it only takes one big thunderstorm and that 'Dry Spring' record set in 1976 remains intact.....and by the way, the grass really did turn brown by the end of that Summer, all of it!

Not enough rain.....yet.

2011-05-08T06:14:00.001-07:00

The heaths around London were tinder dry after weeks without significant rain, but west of London there were 9 or 10mm of rain during Saturday with parts of west Surrey having several millimetres more than that. Unfortunately most of east Surrey and south London had considerably less rain with typical totals 2 or 3 mm. In this part of south London the total rainfall since 1st March is only 21mm, still 19mm short of the 40mm that is needed to prevent Spring 2011 being the driest since before 1900. So, just 24 days left before 'Summer' arrives and will the record be broken. Obviously too early to say yet, and in showery weather totals can increase quickly. However, over the next few days it looks as if showers will be few and far between in this area, and although the further outlook remains generally unsettled, whilst the main area of cyclonic activity stays to the north of Britain, the prospect for substantial rain in south London stays small.

April 2011....a remarkable month

2011-05-03T03:48:00.000-07:00

April 2011 was a sunny month, about the 15th sunniest since 1900. It was also a dry month, the 2nd driest since 1900 behind the April of 1938. It was also the driest early Spring (March/April combined) since 1938. However, the most remarkable feature about April 2011 was the temperature. It was the warmest April since reliable instrument records began in the 19th century, and in doing so beat the outstandingly warm April of 2007. To put the event into perspective statistically; the mean temperature for April 2007 was 13.0, which was a massive 1.4 Celsius higher than the previous record set in 1943. The mean temperature for April 2011 was 13.6! If the month was May instead of April it would have been ranked the 21st warmest May since 1900. The very dry ground aided overnight cooling, and although no air frosts occurred, the mean minimum temperature was only 2.5 Celsius above normal. The mean maximum temperature (19.3) was 4.9 Celsius above normal. This figure was truly incredible. Since 1900, there have only been 8 Mays with higher average maxima. None of these warmer Mays occurred between 1923 and 1988 inclusive. Not only were April 2011 days warmer than most May days, there were several summer months in recent years that have been cooler by day: namely the Junes of 1953,1954,1955,1956,1971,1972,1977,1978,1979,1980,1981,1985,1987,1988 and 1991: the Julys of 1954 and 1980; and the Augusts of 1956 and 1963. What next?

A mild February. Nature redresses the balance.

2011-02-17T06:33:00.000-08:00

Although cold air continues to lurk uncomfortably close on the near continent, forecast charts for the remainder of the month generally suggest that mild weather will prevail. In fact the projected mean temperature in this area of 7.8 Celsius would rank February 2011 as the 4th mildest in the last 110 years, behind 2002, 1990 and 1961. In February 2002 there were no exceptionally mild days, but only 2 air frosts occurred in this snow-free month. In February 1990 there was sleet early on the afternoon of the 3rd, but only 1 air frost occurred and on the 23rd the afternoon temperature soared to a record-breaking 19.0 Celsius. In February 1961 there were several very mild, sunny days and the month was totally free of air frost and snow. Although this February is not going to be a record breaker it has certainly helped to redress the balance after the cold December.

The media snow circus has begun

2010-11-25T05:02:00.000-08:00

The cold weather has arrived and journalists are posted in every corner of the land for the big chill. In reality, it may be the start of something big but in this area no records (yet!). A few flurries of snow around London are not unusual in November. Two years ago there was 1cm of lying snow on the morning of the 23rd. The last time we had a November day colder than today was 17 years ago, on the 22nd to be precise, when the maximum temperature was only 1.2 C. November 1993 was very different to November this year with plenty of cold weather and several very frosty nights with minima below minus 4 C. By the way, December 1993 was mild with only 4 slight frosts, and the lowest temperature only minus 1.2 C!

For snow and cold weather lovers late November 1890 was interesting. After an unremarkable early part to the month, the temperature at Kew exceeded 14 C on the 23rd. However, 5 days later the maximum was only

minus 3.6 C. The following December was the coldest on record. Although it was a relatively dry month, it was very dull with less than 1 hour of bright sunshine all month. Despite the extensive cloud cover, there were only 4 frost-free nights, and after a maximum temperature of minus 6 on the 14th, the minimum on the following night was minus 12 C, a value we haven't seen in this area since 1981!

Early sharp frost,but no record

2010-10-21T05:52:00.000-07:00

The air temperature here fell to minus 2.7 Celsius last night.This was the lowest temperature in October since 28th October 2003 when a similar value was recorded. No monthly record was broken but the lowest temperatures have usually been logged during the last week of the month, and only on the 19th October 1926 has there been such a cold night in this area so early in the autumn during the last 110 years. At that time this area was given over to farmland!

The lowest temperatures measured in south London occurred relatively recently in October 1997. After a very dry September, some heavy rain occurred between 6th and 14th October and this took the monthly total above average. However, after mid month, rainfall totalled less than 2mm with sunshine helping to dry out the ground. The drying process accelerated during the last week as high pressure became established, the air descended and from the 28th until the end of the month the low-level inversion dissipated and all cloud, apart from some cirrus on the 30th, disappeared.

Very low humidities, light winds and dry soils combined to produce the perfect recipe for frost. Nature didn't disappoint with record-breaking low night-time temperatures on both the 28th/29th and 29th/30th. Wallington and Twickenham both recorded minus 5.2 Celsius on the 28th/29th, and here in Morden, after a minimum of minus 4.7 Celsius on the 28th/29th, the following night had a low of minus 5.0 Celsius. Perhaps more remarkable were the grass minima. Values of minus 13.2 and minus 12.8 over the 2 nights remain the lowest 2 consecutive grass minimum temperatures of ANY month since records began here in 1988. By the way, the grass minimum temperature last night was only minus 4.9 Celsius.

2010-04-23T03:27:00.000-07:00

Today marks the 15th consecutive day without measurable rain (defined as 'no daily rainfall equal to, or exceeding, 0.2mm/0.01 ins.'). Up until the 1980s this 15-day period was known as a 'drought'. However, the rise of the mocking tabloid press, the general decline in exactitudes, and comparisons with life-threatening water shortages in the Third World quite correctly brought about the abandonment of the term 'drought' by all but a few diehards.

Nevertheless, it's interesting to examine these lengthy dry spells. The previous one occurred here from the 16th September to 2nd October 2009 (a total of 17 days), but lack of rain is generally less common during the Autumn and Winter months. A good Summer often produces a prolonged period of dry weather. In 1959 this area had 37 consecutive dry days (15th August to 20 September) and in 1976 parts of southwest England had no measurable rain for 45 days. Perhaps surprisingly there was no 15-day dry spell in 2003, but the rainfall deficit for the period February to October in that year was well over 50%.

The Spring months seem to have the most frequent dry spells. In recent years there have been several in mid Spring. In 1995 there were 19 dry days (29th March-16th April), in 1997 it was dry from the 25th March to 17th April (24 days). A total of 27 dry days occurred between 21st March and 16th April 2002, and in 2007 there was dry weather between 31st March and 22nd April (23 days).

Is there any way of connecting dry Aprils to the following Summer? Fortunately the answer is no. In 1912, parts of London had no measurable rain during April and the following Summer was one of the coldest and wettest on record! By the way, the previous 4 mid Spring dry spells were equally divided between good Summers and decidedly indifferent ones.

So how bad has the winter been?

2010-02-10T05:57:00.000-08:00

Days are still chilly, and there was even a flurry of snow early this afternoon. However, the push from winter to spring is well under way.

For statistical purposes, winter covers the 3 calendar months of December, January and February. In this area, December was the 29th coldest since 1900, but in recent years the Decembers of 2002, 1997 and 1996 were colder. January was slightly more interesting. It rated as the 12th coldest since 1900, with colder Januaries occurring back in 1987, 1985 and 1979.

A third consecutive winter month with temperatures significantly below average is quite rare. The last occasion this occurred was during the memorable winter of 1962/3. In more recent years, the winter of 1984/5 was the 10th coldest since 1900 despite a relatively mild December. Similarly, December 1978 was not cold overall, and the winter of 1978/9 was only rated 7th coldest.

Although this current February is only ranked 50th coldest at the moment, it does look as if this figure will rise towards the top 20 over the next few days. However, the trend to milder weather later in the month is apparent from some forecast charts. If, therefore, the mean temperature at the end of the month is similar to the current value (4.9 Celsius), This February will have been the coldest since 1996 and the winter will have been the coldest since 1990/1. However, if this February is cold enough to rise to 20th, it will have been the coldest February since 1991, the 9th coldest winter since 1900, and making it the coldest winter since Jim Callaghan's 'Winter of Discontent'......1978/9.

We await with interest!

The end of the dry spell

2009-10-04T08:27:00.000-07:00

After 17 days without measurable rain, the 0.2 millimetres that fell yesterday evening was enough to break the dry spell. Most years have a prolonged dry spell (15 days or longer) with Spring and Autumn months most likely to see one. September and the beginning of October have had 3 dry spells in recent years. 1997, 2002 and 2007 each had between 15 and 17 consecutive dry days, and back in 1969 only 3 millimetres of rain fell throughout September. The most prolonged autumn dry spell in the London area occurred from the 14th September to 9th October 1921 (26 days). However, there were several lengthy dry periods that began in August, notably 23rd August to 28th September 1929, and 15th August to 20th September 1959, both 37 days. In the extended good summer of 1959 there was a further 17 days of dry weather from the 23rd September until 9th October.

Not a vintage August.....but

2009-08-22T08:01:00.000-07:00

In recent weeks there have been less grumblings about the poor summer. In fact, in the London area August has been a month of consistently warm weather. The temperature has reached, or exceeded, 20 Celsius on every afternoon since 20th July, a total of 30 days! If maxima reach 20 Celsius on each of the next 9 days, then this August will be record-breaking. Even in the hot Augusts of 1995 and 2003 there were days when the temperature failed to reach 20 Celsius, and further back the August of 1976 had some cool days during the last week. It remains to be seen if this month produces a record, but in this so-called poor summer there have been 72 days (including April and May) with highs of 20 or more. In the memorable summer of 2003 there were 117 warm days, including 22 maxima above 20 Celsius during September.

A barbecue summer

2009-08-04T04:53:00.000-07:00

As the baying pack from the media continue to taunt the rather disingenuous attempt by the Met. Office to tell us it almost is a 'barbecue summer', let's find a few facts ........at least for this part of the country where 15 million potential barbecuers live.

There is a reason why barbecues are more common in Mediterranean countries and the USA than here. They have warm and dry summers, and we don't. Up until the mid 70s plastic macs donned for a trip to the pub were more common than plastic plates and cups on the patio, but then the summer of '76 arrived. The general public realized that the sky didn't leak every day, and suddenly al fresco hit London. The barbecue grills rusted for a while in the late 70s and 80s, but from the end of the decade onwards a barbecue grill became a 'must have' along with the 4-wheel drive and a mobile phone. In many years the weather co-operated, but in this summer, like in its two predecessors, plastic mac days returned.

The official statistics put an emphasis on the mean temperature and the total rainfall, but if the nights are cloudy and windy they're often milder than after warm and sunny days. Perhaps more relevant are 'days' with rain falling and daily maximum temperatures, and these paint a poorer picture of the summer weather so far this year.

May, perhaps perceived as a tad early for a trip outside, did produce a few reasonable days during the last week, and June was a pleasant month in London. However, using maximum temperatures, it ranked cooler than the recent Junes of '76 , '89, '92, '96, '03, '04 and '06. Although rainfall totals were below average, the number of days when rain was recorded was above normal

For many people in Southeast England July was a poor month. After the 2nd, winds were from the southwest on nearly every day. The breezes were brisk at times and on the south coast they were often fresh or strong. The temperature has failed to rise above 21 Celsius since 3rd July on the Sussex coast, and although it has been somewhat warmer at times inland, in south London there have only been 4 cooler Julys (based on maximum temperatures) in the last 20 years! The other interesting statistic is with regard to rainfall. Okay, it was a wet month around London, but not exceptionally so. However, measurable rain fell on 20 days.....4 more than the previous July record during 20 years of observations, and what's more 6 of the remaining 11 days had some rain, but not enough to measure.

The Met. Office have 'revised' their forecast for the rest of the summer, but while they keep digging their hole, it remains to be seen if nature has the last laugh and produces a warm and dry August.

The Summer when the grass turned brown.

2009-06-19T03:31:00.000-07:00

For many parts of southern England June looks like being the 4th consecutive month with below average rainfall, but at the moment the fields and gardens are as green as in the Emerald Isle. Not so in June 1976. March and April were both very dry in that year, with monthly rainfall totals in southwest London below 10 millimetres. May was slightly wetter, but still with a total rainfall more than 50% below average. It was a sunny Spring, but May was actually cooler than this May (2009). June 1976 began fairly cool and changeable. The temperature on the 1st only reached 19 Celsius and nearly 2 millimetres of rain fell overnight. The following 2 days were even cooler with highs of only 16 Celsius, but then pressure rose and so did the temperatures. The maximum on the 9th reached 30 Celsius, and although temperatures then fell closer to average, it remained largely dry with sunny spells. During the third week it was rather cool and changeable, and on the 20th nearly 7 millimetres of rain fell, but the last 10 days of the month were dry, hot and sunny. On the 22nd the temperature reached 27 Celsius, but then daily maxima read:- 30,31,33,33,34,33,29 and 29. It came as no surprise that the grass turned brown. It was not even a surprise that pubs around London ran out of beer. The Summer of '76, a record-breaker.

It Never Rains but it Pours

2009-06-07T06:11:00.000-07:00

The proverbial phrase in the title must be going through the minds of many members of the Labour Party, and is probably reinforced by the real thing falling from above.
As further storm clouds build, it's interesting to reflect on how bad June can be, meteorologically speaking of course.
The June of 1972 is often quoted as a bad one, but although it was very cool, the coolest in London since before 1900, it was also dry and not unduly dull.
The majority of very cool Junes have been wet, but given the thundery nature of rain in some summer months, wet Junes are not neccessarily cool. In June 1971 it was cool, very wet and also fairly dull, but for overall unpleasantness 1916 is probably the June winner. Apart from occurring in the middle of the 'Great War' this month was notable for persistently low temperatures and a huge sunshine deficit.
Last June (2008) was not too exciting, but since the cool 1991 June, the month has generally been noted for high temperatures (4 in the all-time top 10) and with only 1998 in the top 10 for high rainfall (90mm and placed at number 10!). It remains to be seen what the rest of this month brings, but even if it is as poor as 1991, there is hope. The storm clouds cleared in that year and gave a very uplifting July, August and September.

That magic 70 mark

2009-05-12T04:06:00.000-07:00

April was the 3rd warmest in this area since before 1900, BUT, the temperature failed to reach 70 Fahrenheit (21.1 Celsius), the much quoted value favoured by the tabloid media. So far, the maxima have not exceeded 21 Celsius this month either, and that is more unusual. In 20 years of records in Morden, the temperature had always reached 21 Celsius by this time of year. As the blustery northeast wind continues to bend the trees under cloudy skies, there seems little prospect of higher temperatures in the immediate future. A scan through the records reveals 1975 as the last year when the temperature stayed below 21.1 Celsius until the end of May but, after a cold start to June, that Summer became very good. Prior to that, the year 1972 had no maxima above 21 Celsius by the end of May, but the June of that year also had no highs above 21 Celsius! The June of 1972 was the coldest of the century, and the rest of the Summer, although dry, was unpleasantly cool.

Yes, it's Spring

2009-03-24T01:38:00.000-07:00

Yesterday, the first significant rain since the 10th March occurred. It marked the end of a very sunny, and mild, spell of weather that has helped to push Spring briskly forward after the relatively cold Winter. In Morden, March is, on average, the driest month of the year. There have been 10 Marchs in the last 100 years when less than 10mm of rain were recorded in the area, the most recent being in 1990 when 5mm fell. The driest March was in 1929 when just 1mm of rain was measured. By way of a contrast, the cold and snowy February of 1947 was followed by a very wet March with 118mm of rain falling in southwest London. It remains to be seen at what end of the rainfall statistics spectrum the final figure for this March will lie.

When will a cold month signify global warming?

2009-03-02T03:32:00.000-08:00

Spring has been rapidly catching up during the recent mild spell, but although February temperatures were below average it was only the coldest for 3 years! Interestingly, the temperatures have been below average in all bar 2 of the last 12 months. A worrying trend towards global cooling? ....er, no. Firstly let's look at these statistics. They relate to a garden in south London and cover the values since 1988, a mere 20 years. Official climatological statistics cover a period of 30 years. The current period that is frequently alluded to by the media covers the years 1971 to 2000. It could be argued that the temperatures derived from these data sets are anomalously high, containing, as they do, more than their fair share of both mild winters and warm summers. However, when figures for the years 1941 to 1971 are compared to those from 1971 to 2000 they show considerable warming, a point not lost to advocates of global warming. In 2 years time the latest set of averages will appear, and they will probably show further warming. The tyres on the global warming bandwagon may then begin to deflate as monthly comparisons with the new figures are increasingly likely to show 'cooler' months unless there is a consistent temperature rise. It could become a very frustrating time for politicians trying to persuade a sceptical public that a 'cold' month would have been defined as a 'warm' month 30 years ago!! By the way, the period February 1900 to December 1902, a total of 35 months, only produced 6 months with above average temperatures.......but that was long before global warming.

The worst winter in living memory (depending on age!)

2009-02-14T02:02:00.000-08:00

It has probably been the worst winter for reporting weather facts since records began, but what about some real statistics. Okay, that's boring, but with the media telling us that the 'Big Freeze' is over it may be time to put some sobering thoughts together. Comments at the local bus stop range from 'Don't remember a winter like it' to 'Winters were often like this when I was young'. Well, yes, both statements could be true, depending on age. The Met. Office defines 'winter' as the three months December, January and February. In this winter, none of the months have been record-breaking in this area. December was the coldest since 2001, January was the coldest since 1997, and this month, although the coldest since 1986 at the moment, will probably end up as the coldest since 1991 or perhaps 1996. So, certainly no extremes there. The 'winter' started early for the media with October snow around London, and further snow fell in November, although that month, as a whole, was milder than average. Of interest, is the fact that the three winter months (unless the rest of February becomes very mild indeed!) have all been colder than average and the mean temperature is comparably cold with only 3 winters during the last 30 years. There is no way (famous last words!!) that this winter will be as cold as that of 1978/79, but it will probably be the coldest since 1995/96, perhaps the coldest since 1990/91, and maybe the coldest since 1985/86. If colder weather returns at the end of the month, then it will be the coldest winter in this area for 30 years, and for many, many people that's outside of 'living memory'.

A Rare 'Since Records Began'.

2009-02-10T05:56:00.000-08:00

After 20 years of noting the daily weather, it becomes increasingly rare for new records to appear. Yesterday was one of those record-breaking days. The rainfall total, 22.0mm, beat the existing February record, set on the 24th in 2000, when 21.1mm fell. High daily rainfall during February is quite unusual, and in this area a total of 20mm appears to have been exceeded on only 3 more occasions. Namely, in the years

1925, 1933 and 1951. The wettest day was the 13th February 1925 when between 25 and 30mm of rain fell locally. Of interest, but not statistically significant so early in the month, a wet February in this area, with rainfall over 70mm, has only been accompanied by a cold February, with a mean temperature below 4.0 C, on one occasion since 1890, and that was in 1900! Another 18mm is needed to keep the rainfall part of the record at this site, and with a mean temperature of 1.3C, some mild days (and nights) are needed to spoil the other half of the potentially record-breaking equation.

The heaviest snow in South London since.....

2009-02-02T05:54:00.000-08:00

The 19 centimetres of snow that fell yesterday and overnight has got us trawling through the record books. 'The snowiest since February 1991' is a typical quote from the media, but in that month, the Morden area only had 16 centimetres of level snow. Back in January 1987, it was bitterly cold and there were some deep drifts, but again the level snow was only 16 centimetres. Snow stayed on the ground for a while in the winter of '81/82 but not particularly deep, and then it's back to the 'winter of discontent' - 1978/79. Certainly on hills, and particularly in north London, snow depths exceeded 20 centimetres, but not in Morden. Early March produced depths close to 15 centimetres, but December 1962 had heavy snow on Boxing Day http://www.london-weather.eu/article.102.html, followed by further significant falls later in the month. The resulting depth was 25 to 30 centimetres. That's where the record lies.... so far!

'Snow Breaks the Drought'... but not any more

2009-01-05T04:17:00.000-08:00

The light snow that fell overnight and early this morning marked the end of a 16-day period without measurable rain. In the old days, when City gents wore bowler hats and Christmas crackers only came from Woolworths, a spell of 15 days, or more, without 'significant' rain (less than 0.01 inches, or 0.25 millimetres) was known universally as a 'drought'. It was a term reluctantly used by meteorologists but regularly dug up by the media. Fortunately, since the real droughts, especially in Africa and Australia, have been vividly portrayed on our television screens, a lack of rainfall has been taken more seriously. However, to get back to the quirky old 'drought'. There have only been 3 occasions during the last 20 years in this part of London when a 15-day dry spell has encompassed the winter months (December, January and February) and not at all when the majority of dry days occurred during December! The 16 consecutive 'dry' days is nowhere near a record. In 1959, http://www.london-weather.eu/article.99.html central London had no measurable rain from the 24th January to 20th February, a total of 28 days.

Wettest day of the year in London?

2008-12-14T03:45:00.000-08:00

Yesterday was the wettest day of the year with 25.4mm (exactly 1 inch) of rain falling in the 'Rain day' that stretches from 09 to 09 GMT. It was not a record breaker, nearly 32mm fell in December 2002 and almost 30mm fell in 1995. Boxing Day 1886 appears to have been the wettest December day, but as some of the totals included melted snow a cynic may question the validity of the readings. The numbers for that day included 46mm for Kensington and Brixton and 60mm for Hampstead. In recent years, 34mm fell in parts of southwest London during December 1979. Interestingly, the whole rainfall event this December covered 2 'Rain days' and the total came to nearly 36mm. It commenced around 0100 hours on the 13th and then rained continuously until 2300 hours, a total of 22 hours. That in itself is not a record. During June 1903 parts of north London had over 58 hours of continuous rain. By the way, a few days after that rain a three week 'drought' commenced!

Sunny Weather in London

2008-12-01T11:49:00.000-08:00

After 3 dull days the sunshine that arrived today was to be welcomed. If it wasn't for a few minutes of low cloud at either end of the day the sunshine could have been unbroken. The 1st of December is potentially the sunniest day of the month with the daylight fractionally longer than on any other December day. This potential is seldom realised of course, but in 1954, a mild and sunny December occurred, and there were 7 hours of sunshine on the opening day. Two years later it was also mild during December but there were only 9 hours of sunshine all month. The Clean Air Act of 1956 helped to reduce pollution in London and smog is now almost unheard of. Fog is also a rarity now in Greater London, and the dreadfully dismal months of the 19th and early 20th centuries are behind us. There will probably never be a repeat of December 1890 when much of London had less than 30 minutes of sunshine all month, and parts of the West End remained completely sunless.

Wettest day since......?

2008-11-11T01:50:00.000-08:00

Yesterday (10th November) nearly 24mm of rain fell. This made it the wettest day of the year so far and the wettest day since November 19th last year. November ranks, on average, as the wettest month of the year in many parts of the country, but in the last 20 years, in this area, October has been a wetter month. A daily rainfall total of 24 mm in November is actually not uncommon here. It has occurred 4 times during the last 20 years, and 3 of those occasions have been during the last 8 years. On each of the last 3 very wet November days, more than 30 mm of rain have fallen. The wettest day was the 5th November 2000 with 33 mm of rain. The wettest day in the area from historic records appears to have been the 25th November 1938 when nearly 42mm of rain was measured.

Frosty October Nights

2008-10-25T04:20:00.000-07:00

The grass temperature fell to minus 5 last night, the 8th 'grass frost' of the Autumn so far. The minimum temperature forecasts published in newspapers and featured on radio and television broadcasts are, quirkily, based on the expected temperatures in a louvred white box standing in an open position between 1.25 and 2 metres above the ground. Anyone small enough to be sitting in one of those boxes last night would have experienced a temperature of minus 0.3 Celsius, making it the first air frost of the season. During the last 20 years there have been 12 years when air frost was absent during October, but in 1997 air frost occurred on 5 nights during October. The earliest frost was on the night of the 15th/16th October 1993, but in the suburbs of London frost has occurred much earlier in past years. Aside from the notable frost hollows at Chipstead (Surrey) and Rickmansworth (Hertfordshire), one of the earliest suburban air frosts occurred on the night of the 18th/19th September 1952. There was also a frost in southwest London on the 29th/30th September 1919. In October 1888 there were 9 or 10 air frosts across much of London. The lowest October temperature recorded in Morden during the past 20 years occurred on the night of the 29th/30th 1997 when a minimum of minus 5.0 Celsius was measured. A value that could be hard to beat.....maybe!

Last of the Summer Days?

2008-10-12T07:17:00.000-07:00

Time to get the potatoes in before Autumn truly arrives. Although temperatures above 20 Celsius in October are not unusual, after the disappointingly cool September in London, this short warm spell is much welcomed. The maximum temperature of 22.2 Celsius today is over 1 degree warmer than any maxima recorded during September, and is the highest this late in October since 2001. There were only 4 days during August that were warmer, 13 days in July and 7 in June. In October 1921, the first 11 days of the month had maximum temperatures above 21 Celsius, and on the 5th and 6th of October in that year the high was close on 29 Celsius at several places in London, including Kensington Palace, Greenwich, Camden Square and St James's Park.

2008-09-23T05:02:00.000-07:00

Although rain threatens for the next couple of days, it's now 11 days since any measurable rain fell in Morden. With little, if any, rain likely during the last week, it looks as if September is going to be another dry month. That will make 3 out of the last 4 months with below average rainfall; and 6 out of the last 7 months have had temperatures below the 20 year average. The scientific community regularly assure us that the very wet weather (but not everywhere!) is part of global warming, and the El Nino is responsible for the lower temperatures. Of course, the threat of Global Warming cannot be ignored, but perhaps the trend towards sixties fashions has been followed by a return to sixties weather. Let's hope not. Apart from the severe winter of '62/63 most of the weather was instantly forgettable. Some of the fashions and much of the music appear to have lasted in the memory somewhat longer.

The Screen has a make over.

2008-08-20T05:16:00.000-07:00

Every now and again the screen housing the thermometers needs renovating. With no spare available, a little improvisation is called for to maintain reliable temperature readings. The 'Official' box, temporarily absent for repair, spent many years housing thermometers on State House, a high-rise office block in High Holborn, London. The block succumbed to concrete rot and has since been replaced, and the 'London Weather Centre' that used to take readings from it's base opposite in Penderel House has long since moved on. The Stevenson Screen, the official name for the louvred 'bee-hive' box was invented by Thomas Stevenson in 1864. He was a civil engineer responsible for the design of many lighthouses but the screen is maybe his enduring legacy. The World Meteorological Organisation recognize the Stevenson Screen as the standard housing for meteorological instruments. It has to be in an open area between 1.25 and 2 metres above the ground. Originally this screen was around 80 metres above street level. It has led a Jeckyll and Hyde existence, perhaps appropriate considering the inventor was the father of Robert Louis Stevenson, the author of The Strange Case of Dr Jekyll and Mr Hyde

2008-08-07T05:50:00.000-07:00

To put it simply, there are 3 main types of thunderstorm in this country. The most common of these is the all-year-round storm which starts with a build up of cloud during the morning, a couple of rumbles from a cumulonimbus cloud in the afternoon, followed by a fine evening. In the winter months this type of storm is usually found on windward coasts. The second type is formed by the destabilisation of the air well above the surface, usually 6,000 feet AMSL or higher. This commonly occurs when cool Atlantic air is about to bring an end to a hot spell. In recent years this form of storm has been fairly uncommon, although one occurred here on the 28th July. The first sign of these type of storms is usually several afternoon reports of thunder from Brittany, followed by a quick migration northeastwards, reaching Southampton in the early evening and London bewtween 9 and 10 pm. For the good folk of Kent last night's storms were closest to the second category. Although very little surface wind blew in association with the storms, it was certainly not true that they were slow moving. In fact the storm clouds were moving at around 35 knots. Rather than one storm lasting a long time, it was a series of storms generating within a band that ran from the East Sussex coast towards Essex. Now, the third type of storm is the 'swing-seat' one. This occurs on a warm summer's evening when several storms develop or move into the area, produce a vivid display of lightning, numerous rumbles of thunder, but are never overhead. Thus, it remains dry and warm, and a free display of nature's power can be observed accompanied by a glass of claret and a packet of peanuts. That was the thunderstorm that occurred over this part of South London yesterday evening.

Where is the Summer Heat?

2008-07-25T04:24:00.000-07:00

Yesterday (Thursday) was the warmest day of the 'Summer' so far. Here in Morden, the temperature reached 27.6 Celsius, central London and and Northolt reached 27.5 Celsius, and Heathrow Airport managed 28.2 Celsius. Today is less warm, but humid, and over the next few days it looks like being warm but probably not hot. In the London area there is usually at least one day in the Summer when 28 Celsius is comfortably exceeded, and, of course, there is still plenty of time for high temperatures. In recent years, some record-breaking maxima have occurred during August. However, if the 27.6 Celsius should prove to be the highest maximum, it would then be the lowest yearly maximum since 1978!

Not Another Wet July!

2008-07-03T04:37:00.000-07:00

The first rain of the month has just fallen but there's a long, long way to go before we reach last July's total of 124mm. It was the second wettest July for at least 100 years in South London, with only July 1956 wetter. Perhaps surprisingly, none of the top 10 wettest Julys correlate with the top 10 coolest Julys. During the wet Julys, rain is often of a thundery nature, and although the weather may be cyclonic, there are often spells of warm sunshine between the downpours. However, out of the 9 Julys when 100mm was exceeded, only the Julys of 1925 and 1941 could be described as rather warm. In association with all the wet Julys, the following Augusts were cool, and sometimes very cool. Let's hope it's not another wet July this year.

Cool Junes

2008-06-06T03:48:00.001-07:00

The last time that temperatures were below normal during June across south London was in 1991, so statistically we are well overdue for a cool June. To add to the statistical woes, 3 out of the last 5 Junes have been 'top ten' Junes. In other words, amongst the 10 warmest Junes since 1900.

During the '70s and '80s poor Junes were in the majority. In fact, only 2 Junes in each decade could be described as warm; those of 1970, 1976, 1982 and 1989. This early summer month was particularly poor in 1971 and 1977, but in 1972 the coldest June of the century occurred with the the temperature failed to rise above 20 Celsius all month. The 3 disappointing Junes in the '70s were all dull, and 1971 produced the second wettest June of the century. Rainfall was above average in June 1977, but perhaps surprisingly, June 1972 was a very dry month in South London. Looking at the synoptic charts for the month, it certainly appeared very unsettled, but Atlantic rain bands only yielded small amounts of rain, and the 'showery' air behind the fronts only produced limited amounts of convection. However, after a sunny start to these days, cloud developed during the mornings and spread across the sky to produce gloomy, but mainly dry, afternoons, the worst type of summer weather.

Rain Records? No.

2008-05-28T05:16:00.000-07:00

The 54mm of rain that have fallen in Morden during the last 4 days have certainly made the ground soggy. However, the first 23 days of the month only yielded 7mm of rain. So no records, at least so far. During the last 110 years, there have only been 2 Mays when rainfall exceeded 100mm in south London, namely in 1932 and 1979. Statistics will show this to be a wet month, but for much of the time it has been dry and warm. May 1992 was similar in many respects. It was a very warm month with plenty of sunshine, but there were 65mm of rain, 54mm of which fell on just 3 days. At Heathrow Airport, there was a total of 95mm, with nearly 62mm falling on the 29th. The wettest May day in the last 100 years occurred on the 31st May 1911. At Banstead, over 91mm of rain fell, over 81mm fell at Harrow, and nearly 73mm fell at Epsom, of which almost 62mm fell in just 50 minutes. This became known as the 'Derby Day' storm, on account of the 5 people that were killed by lightning at the end of the Epsom Derby. Several other people were struck by lightning, including a police cyclist who died in Garth Road, Morden.

Warming up again

2008-05-21T03:30:00.001-07:00

Now it's warming up again, the risk of air frost has probably gone until the autumn. The minimum temperature (2.2 Celsius) that occurred the night before last, was the equal lowest during the second half of May in Morden for at least 20 years. A similar minimum occurred on the night of the 28th/29th May 1994. An air frost did occur in a few places on Monday night, with minus 0.3 Celsius recorded at Farnborough (Hants). The cold air originated north of the Arctic Circle, and when it crossed Finland, minima of minus 10 Celsius occurred, resulting in much damage to apple blossom.

The Return of the Rain

2008-05-16T03:34:00.000-07:00

The warm weather abruptly ceased yesterday as the first measurable rain for 11 days occurred. The heaviest rain fell before 0900 UTC and was accredited to the previous day. Generally, amounts of rain in the London area were fairly small, with the more persistent rain occurring over counties to the north of the Capital. Further heavy rain is forecast, but looking through the records for south London during the last 20 years, high rainfall totals are not particularly common. There have been only 10 days during May with rainfall above 15mm. The wettest May day, with 24mm, occurred on the 27th last year.

Continuing May Warmth

2008-05-11T07:18:00.000-07:00

Nearly one third of the month has gone and temperatures are heading towards a new record, but are they? The year 1992 had the warmest May on record in south London, with May 1989 only a fraction of a degree cooler. In May 1992, most of the very warm days occurred during the second half of the month, with several decidedly chilly days during the first fortnight. It is very unlikely that the present warm spell will persist, but a very pleasantly warm May, so far.

Late Spring Warmth

2008-05-06T07:21:00.000-07:00

The temperature exceeded 22 Celsius for the third consecutive day today. The last time this happened was between the 5th and 7th September last year. During May last year there were 4 consecutive days late in the month with highs above 22 Celsius and there were also 3 consecutive days above 22 in April. The longest sequence during the last 20 years of 22+ days (9) in May occurred during 1998, from the 8th to the 16th. After a maximum temperature of 21.4 on the 17th, there were then another 3 consecutive days with highs above 22 Celsius. By way of contrast, in May 1994 the temperature failed to rise above 22 Celsius all month!

May Frosts?

2008-05-04T03:55:00.000-07:00

Last night the temperature failed to fall below 13 Celsius (55F), the mildest night since 16th October. No doubt the Garden Centres will increase their sales of bedding plants, helped by the occurrence of the holiday weekend. However, before last night, there were 2 nights with ground frost. In this part of the country, there has only been 1 May during the last 20 years when ground frost was not reported, and in 2 years there were damaging air frosts with the temperature falling below minus 1 Celsius (30F). A few years ago, a well-respected local gardener said 'never put in frost-prone plants before 17th May'. Good advice, well received.

A thundery start to May

2008-05-01T12:58:00.001-07:00

The thundery start to May is nothing unusual. This late Spring month often has a spell with thunderstorms, and it's now 12 years since the last thunder-free May. In both 2001 and 2002 there were 5 days when thunder occurred. Today, a line of showers continued to feed northeast across London. Similar lines of showers occasionally cause problems during the Wimbledon Tennis Fortnight, and like this afternoon, skies were fairly clear both north and south of the Capital. Although southwest winds blew today, May is frequently a month when northeasterly winds dominate. We await the rest of the month with interest.

A Wet April Day

2008-04-30T10:22:00.000-07:00

Yesterday was the wettest April day in Morden for 15 years. Much of the rain fell today (30th) but a 'rain day' runs for 24 hours from 0900UTC.

The 17.5 mm was eclipsed by the 27.8 mm that fell on the 1st April 1993 and the 31.2 mm that was recorded on the 29th April 1991. On the 10th April 1878, a total of 99 mm of rain fell at Haverstock Hill (Highgate).

Over the last 20 years, April has proved, on average, to be the wettest Spring month, but this year it looks as if March will take the honours.