London Weather in September
In September, London averages a high of 19°C (66°F) and a low of 11°C (51°F), from 46 years of daily records (1971–2025).
19°C
Average high
66°F
11°C
Average low
51°F
33°C
Record high
91°F · September 9, 2023
2°C
Record low
36°F · September 30, 1974
What September Is Like in London
- London's hottest September day on record is a recent one: 33°C (91°F) on September 9, 2023.
- The coldest September reading, 2°C (36°F) on September 30, 1974, has not been matched in 51 years.
- The warmest September in the record was 2006; the coldest was 1972.
At least 1 mm of rain falls on 29% of September days, and the month averages 58 mm in total.
Warmest: 2006 (22.2°C)Latest: 2022 (20.3°C)10-year averageLong-run average (18.6°C)
Look Up a Day in September
See the weather in London on any September date, year by year.
Source: NOAA GHCN-Daily, Hampstead (1971–2016); Heathrow (1986–2025). Averages cover 1971–2025. How we compute this