The climate in London during September can be summarized as mild and reasonably dry.
September is in the fall / autumn in London and is typically the 4th warmest month of the year. Daytime maximum temperatures average around 19°C (66°F), whilst at night 11°C (51°F) is normal.
|Daytime temperature||18.9°C 65.9°F|
|Nightly temperature||10.6°C 51°F|
|Average temperature||14.7°C 58.5°F|
|Daily sunshine||5.2 hrs|
|Avg rainfall||55 mm 2.2 ins|
|Rainy days||11 days|
|Sea temperature||17°C 62.6°F|
|Windspeed||13.3kph 8 mph|
On average September is the 6th wettest month of the year in London with around 55mm 2.2 inches of rain making it a reasonably dry time to visit. This rainfall is typically spread over 11 days, although this may vary considerably.
On the flip side this corresponds to an average of 5.2 hours of sunshine per day.
The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in London in September 2021.
|Hottest month:||July||21.7°C 71.1°F|
|Driest month:||February||38mm 1.5ins|
|Coldest month:||January||6.8°C 44.2°F|
|Wettest month:||December||59mm 2.3ins|