One aspect of our changing climate has surprised me, and that is the ease with which the general public have forgotten what Britain’s weather used to be like twenty years or so ago. Take last month. The general impression was that it was an unusually cold month with plenty of rain and a shortage of sunshine, and people have been asking me why summer is so late arriving this year. The statistics paint a different picture. For England and Wales at least it was slightly warmer and sunnier than average with a marked shortage of rain. The figures don’t lie; rather, people’s hopes seem to have turned into expectations, and those expectations are not always realistic.

The average maximum temperature for the month ranged from 9.4°C at Fair Isle, between Orkney and Shetland, to 17.8°C at Gravesend in Kent, while the mean minimum ranged from 2.8°C at Kinbrace in Sutherland to 10.1°C in central London. The Central England Temperature, which includes both daytime and night-time readings, was 11.4°C, just 0.1 degC above the average for the standard reference period 1971-2000. It was, in fact, the coolest May for nine years, a reflection of the warmth of recent Mays rather than anything inherently unusual in last month’s weather. This is confirmed by that fact that, over the last 100 years, 43 Mays were warmer, seven had the same mean temperature, and 50 were colder.

There were several notable temperature extremes during the month. The night of April 30 to May 1 was the warmest so early in the season since 1945 with overnight lows of 12-14°C across much of England and Wales, whereas the night of May 17-18 was the coldest so late in the season since 1956 with an exceptional minus 6.3°C recorded at Tulloch Bridge, 24 kilometres east of Fort William. It warmed up again at the end of the month with 31.4°C recorded at Herne Bay in Kent, the highest May reading anywhere in the UK since 1953.

May was a dry month over England and Wales, exceptionally so in the London area, the middle Thames Valley, Hampshire, Wiltshire, and the southwest Midlands, where several places recorded less than one-third of the normal amount of rain, extending the long period of below-average rainfall here to seven months. At a number of sites in southern England it was the driest May since 1991. Scotland and Northern Ireland were, by contrast, rather wet, and the month’s rainfall at Loch Glascarnoch in Wester Ross was double the l ong-term average.

Sunshine aggregates were above the long-term average in all parts of the country, largely thanks to some very sunny days during the second week. Along the east coast of Scotland and in parts of the Midlands and eastern England, several places recorded 20-25 per cent more sunshine than usual. However, the biggest total was at Shanklin on the Isle of Wight with a monthly total of 265 hours – around 8.5 hours per day.

© Philip Eden