Another wet and cool day to end the month plus September review

With another 10.3mm of rainfall and a maximum almost 3C below average, Monday was a sad autumn day to finish the month. There just a few minutes of brightness during what was a cloudy but less breezy day.

Tuesday saw a predominantly cloudy start with very brief glimpses of sunshine that by 08.00 had lifted the minimum of 8.9C, just below average, to 10.0C.

September 2019 Review

September has been a month of extremes. The first 20 days saw little rain, just 7.3mm, with ten totally dry days. Thereafter every day was wet with considerable rainfall.

The heaviest rainfall occurred on the 23rd with a total of 29.6mm, the days on either side each producing thunder on two occasions.

The rainfall for the month amounted to 111.4mm. This was 181% of the 35-year average or plus 50mm also the wettest September since 2006 when a record 131.9mm fell. The contrasting year was in 2009 when as little 11.1mm was recorded. The other significant daily totals were 18.6mm, 23.0mm and 10.0m on the 24th, 28th and 30th respectively.

Due to the high pressure that settled over and around the country for the majority of the month, it was a warm month with the mean temperature 0.4C above the 35-year average. There were seven days when the peak temperature exceeded 20C when the average was 18.6C. The hottest day on the 21st saw a maximum of 24.9C.

No air frost occurred although the thermometer dropped to a minimum of 0.4C on the morning of the 8th that produced a brief ground frost.

The diurnal temperature, which is the variation between day and night, has seen significant changes for some months since my records began in 1984. September has seen the maximum variation increase by about 1C. However, the variations for the months November to February have seen the maximum increase by 2C to 3C.

During the month 168 hours of sunshine were recorded with many days in the middle of the month seeing almost wall-to-wall sunshine. On the 13th 10.25 hours of sunshine were recorded.