Friday, 6 June 2008

Cool Junes

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.