Weather data
The weather of Reading in September
Air temperatures tend decrease throughout September on average, with maximum temperatures in Reading falling from an average of about 20.5 ºC at the start of the month towards 17.5 ºC by the end; minimum temperatures decrease from about 12.0 ºC to about 10.0 ºC. The average temperature during the month is 14.9 ºC at the university. Air temperatures in September have ranged from a summery 31.7 ºC to a wintry -1.1 ºC in Reading. Values of 30 ºC and above occurred, when the site was closer to the town centre than now, in 1911, 1919, 1929, 1940 and 1949 with 31.7 ºC on 7 September 1911 (30.5 ºC occurred four days earlier) and 31.2 ºC on 4 September 1929 (with 30.3 ºC on the 5th and 30.6 ºC on the 8th). Minimum temperatures in September have been as high as 20.3 ºC on 5 September 1949 and 18.0 ºC on 5 September 2006 and as low as -1.1 ºC on 30 September 1919. Air frosts occurred on four mornings at the London Road site in September - on 23 and 30 September 1914 and on 29 and 30 September 1919. 2006 (average temperature 18.0 ºC) and 1912 (11.3 ºC) have been the warmest and coldest Septembers in the record.
The monthly mean rainfall for September in Reading is about 50 mm, but monthly totals since 1908 have ranged from 146 mm in 1974 to 0.8 mm in 1959. 1968 was also a wet month, largely as a result of the 14th and 15th when a total of 70.1 mm fell leading to local flooding. September 1959 was widely regarded as the month when summer ended unusually late in the year; all the measurable rain that month fell on the 21st. Daily falls of 25 mm or more of rain occur in about one year in six in September - but on the thundery days of 11 September 1921 and 20 September 1980 totals of 50.0 mm and 50.9 mm, respectively, fell. However, the wettest day of any month in the Reading record was 22 September 1992 when 76.3 mm of rain fell in 13 hours.
The transition from August to September is marked by a drop in the monthly-mean sunshine duration to 143 h in September - a month with 2.6 sunless days on average. However, in 1959 a total of 224.6 h were recorded. The sunniest day in September might be expected to record in excess of 11 h of bright sunshine and in four years (the September months of 1977, 1982, 1994 and 2003) since 1968 over 12 h of sunshine occurred on one day very early in the month.
Snow has never been observed in Reading during September, but on average thunder is heard on 3 days every 5 years; it was heard on 6 days in 1967. About half of all September months end to be free of fog at 0900 GMT - the monthly average is about 3 days every four years. The greatest wind gusts on record during September are 53 kn (27 m/s) on 27 September 1975 and 56 kn (29 m/s) on 7 September 1974.
All averages refer to the period 1991-2020 unless otherwise stated.
Statistics last updated 1 August 2022.