Sunny, warm and mostly dry is the new September trend
SEPTEMBER was the warmest for 15 years and it was also the second warmest September ever recorded in Leicestershire in records going back to 1836!
Only September 2006 with a mean of 17.2c was warmer than this one. Afternoon temperatures averaged 21.3c which is 2.5c above normal with night time figures averaging 12.2c also 2.4c above normal.
The overall mean of 16.8c was also 2.4c above normal and it came a close second to the record breaking 2006 figure.
The reason for the warmth were the development of areas of high pressure either over or to the East of the British isles. These caused the winds to blow in frequently from a southerly direction bringing with it air from Africa and the Azores and with it the very high temperatures.
The warmest day of the month was the 7th when temperatures at the Met Office site at Sutton Bonington reached a staggering 30.5c and at Hinckley Dean Whitaker recorded 29.9c his warmest September day ever recorded. Nights were also very warm with temperatures at Mountsorrel remaining at 17.6c on the 10th and this figure should have been the average day time max and not the night value!
September was a very dry month for the first 26 days with only 18mm falling up to the 26th. The last four days of the month saw the heavens open however with another 33mm falling at Mountsorrel giving me 52mm around average for the month.
Dean in Hinckley received 57mm which was 98% of his usual total but all this rain fell on just seven days and most of it in the final four!
Sunshine figures were very close to normal with 137 hours being recorded at Dave’s station in Cosby with the sunniest day providing us with 11.8 hours on the 7th. So the month was very warm with a good deal of sunshine and for the most part it stayed dry.
My friend and colleague Steve Jackson, who is in charge of the Coventry weather station, has found that since the millennium the average temperature in September has reached 14.9c.
That’s 0.7c higher than our previous warmest September decade in the 1980s. There has also been 10% more sunshine in this period than before the year 2000 and rainfall has averaged just 49mm each month where as in the 1990s the average rainfall was 76mm each month a reduction of 33%.
So a huge increase in temperature and sunshine in September and a marked decrease in rainfall in the last 21 years! So you have not imagined it, September has been substantially better than it used to be!
Whether this is a long term trend its too early to say but its certainly helped to extend the summer in recent years.
Many thanks to Steve Jackson for the Coventry statistics, Dean Whittaker Hinckley`s own weather recorder and Dave Mutton from Cosby the Mercury weather supremo for nearly 50 years.