London weather in September
September in London: nice, a little rain, with clean air — an excellent time to visit.
#5 of 12 months in London · #268 of 604 destinations to visit in September · comfort 82/100 (tier A)
Updated June 2026 · climate normals from ERA5 reanalysis
London climate normals — September
| Daytime high | 20°C / 68°F | 😎 nice |
|---|---|---|
| Nighttime low | 12°C / 54°F | |
| Feels like (high) | 19°C / 66°F | |
| Rainfall | 55 mm / 2.2 in | 🌦 some rain |
| Rainy days | 10 days | |
| Humidity | 78% | 💦 very humid |
| Dew point | 13°C / 55°F | |
| Sunshine | 8 h/day | |
| Daylight | 12.6 h | |
| Wind | 18 km/h / 11 mph | |
| Air quality (US AQI) | 46 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
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London in September — FAQ
- Is September a good time to visit London?
- September in London: nice, a little rain, with clean air — an excellent time to visit. It ranks #5 of 12 months for London on SeasonMap's comfort score (82/100).
- What is the weather like in London in September?
- In September, London averages a daily high of 20°C and a low of 12.2°C, with about 54.7 mm of rain over roughly 9.6 rainy days.
- What is the air quality in London in September?
- London has a mean US Air Quality Index of about 46 in September.