By Philip Eden

September was a month of two parts. Until the 10th Britain basked in warm sunshine – the first spell of dry and sunny weather since the middle of June – but the remainder of the month was changeable and often windy. There was a great deal of rain in western and northern Britain, but eastern, central and southern regions were surprisingly dry, and here it was the third consecutive warm, dry and sunny September.

Mean monthly temperature was about 1 degC warmer than average in all parts of the UK, but this was entirely thanks to the heatwave during the first week or so; from the 11th onwards temperatures were near normal. The Central England Temperature of 14.8C was 1.2 degC above the average for the standard reference period 1971-2000, and there have been only eight warmer Septembers during the last 100 years, most recently in 1999. The warmest days were the 4th, 5th, 6th, 8th, and 9th when readings of 25C or more were recorded widely; the month’s highest was 29.0C at Wisley in Surrey on the 5th, and this too was the highest for five years. During the second half of the month there were a few decidedly chilly nights, and air frost was recorded in isolated valleys and hollows even in southern England, notably on the morning of the 16th. But the month’s lowest temperature of minus 1.1C was logged at Altnaharra, Sutherland, overnight 13th/14th.

Two-thirds of September’s sunshine was squeezed into the first one-third of the month – the period 1st-10th was the sunniest such since 1933, while 21st-30th was the gloomiest since 1996. Monthly aggregates were above normal almost everywhere in the UK, and it was the sunniest September in the Aberdeen area since 1906.

Even after the weather broke, amounts of rain in southern and eastern England, the Midlands, and parts of eastern Scotland were generally small. Boulmer, near Alnwick in Northumberland, had its driest September since 1971 while Dishforth, near Ripon in North Yorkshire, measured just 10mm of rain – one-sixth of the local average. By contrast, west-facing slopes of the Scottish Highlands, the Lake District, and Snowdonia endured several prolonged and heavy downpours with upwards of 600mm at the wettest sites. Averaged over England and Wales, the month’s total of 57mm was 30 per cent below normal; there were 36 drier Septembers in the last 100 years.

(c) Philip Eden