By Philip Eden
September was dominated by southerly winds to a remarkable extent and as a consequence it was an abnormally warm month – over large parts of the country it was the warmest September on record. The weather was generally settled in eastern and central regions until the 21st with good sunshine records on most days, but rain fell frequently and sometimes heavily during the last ten days.
The mean afternoon maximum temperature ranged from 22.9°C at Gravesend in Kent to 14.2°C at Lerwick on Shetland, while the average night-time minimum temperature varied between 15.9°C at St Catherine’s Point on the Isle of Wight and 8.2°C at Braemar in Aberdeenshire. All these figures are between 2 and 4 deg°C above the long-term average.
As measured by the Central England Temperature (CET) series which takes into account both daytime and night-time readings, the month's final figure of 16.6°C was 2.9 °C above average, thus equalling the previous highest September CET which was recorded in 1729. The nearest approach last century was September 1949 with a CET of 16.3C.
The highest individual temperature during last month was 30.2°C at Heathrow airport on the 11th, the highest September reading in the UK since 1999. The maximum of 29.0°C at Sutton Bonington on the 21st was the highest so late in the year since 1985. The month’s lowest reading was minus 0.8°C at Braemar overnight 7th/8th.
Rainfall during September was very variable, and most of it came in the last ten days. Averaged over England and Wales, the monthly total was 79.2mm which is 4% below the long-term mean. This made it the wettest September for six years; during the last 100 years 40 were wetter and 60 drier. At a local level, totals ranged from 386mm at Inveruglas in Argyll to a mere 16mm at Portland in Dorset.
Sunshine was plentiful until the last week, and for England and Wales as a whole the month's total was 166 hours which is 15% above the long-term average. By this measure it was slightly sunnier than the Septembers of 2005 and 2004, but not as sunny as 2003. Individual sunshine aggregates ranged from just 50 hours at Lerwick to 198 hours at Herne Bay in Kent.
© Philip Eden