Climate summaries

Overview of weather across the UK for previous months, seasons and years

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UK last month

September 2023

High pressure influenced the UK's weather for the first half of September, bringing fine, sunny, dry conditions and the most significant spell of warmth since June. From 4th to 10th, the UK experienced a significant heatwave with temperatures exceeding 30°C somewhere in the UK for seven consecutive days: a September record. Temperatures in England reached 32°C on 6th, 7th, 9th and 10th, and 33.5°C at Faversham (Kent) on 10th, making this the hottest day of the year. This has only occurred in September on four previous occasions in 2016, 1954, 1949 and 1919. On 8th, 28.0°C at Castlederg (County Tyrone) set a new Northern Ireland September record. However, the heat brought several outbreaks of thunderstorms and intense downpours with rainfall rates of 20 to 30mm per hour, with impacts from flash-flooding. The second half of the month saw an abrupt change to much more unsettled and autumnal weather with westerly weather bringing Atlantic low pressure systems and significant rain. There were some very wet and windy days, notably storm Agnes from 27th to 28th, although fortunately the storm was weakening by the time it reached the UK.

Maximum and minimum temperatures for the month overall were well above average, particularly across the southern half of the UK, with maximum temperature anomalies in some parts of the south-east 3.5 to 4°C above average. The UK monthly mean temperature was 15.2°C, 2.2°C above the 1991-2020 average making this the UK’s equal-warmest September in the series from 1884 (shared with 2006). For England and Wales this was the warmest September on record. The rainfall pattern was variable but rather wet overall with 131% for the UK. Some locations experiencing torrential downpours were particularly wet, for example parts of south and east Devon. Sunshine totals were slightly above average for the UK with 112%.

The UK monthly extremes were as follows: A maximum temperature of 33.5°C was recorded at Faversham (Kent) on the 10th, the UK’s highest temperature of 2023. A minimum temperature of -3.5°C was recorded at Kinbrace (Sutherland) on the 13th. In the 24 hours ending at 0900 UTC on the 20th, 117.0 mm of rain fell at Honister Pass (Cumbria). A wind gust of 73 knots (84 mph) was recorded at Capel Curig (Conwy) on the 27th.

Regional values for September 2023