United Kingdom
London in September: weather & travel advice
This month's data profile
Rain shapes the decision
London in September is climatically well suited to city breaks and active holidays and hiking. The average daily high is around 20 °C. With about 11 rainy days it is wet.
Historical monthly averages, not a weather forecast. Individual days and years can differ substantially.
Rank among 12 monthly averages
70/100 · #4
Warmth
#4
Dryness
#5
Sun
#6
Published best categories: Overall, City break, Active
London · SeptemberPhoto: Colin · CC BY-SA 4.0Climate facts
- Average high
- 20 °C
- Average low
- 10 °C
- Rainy days (est.)
- 11 rainy days (est.)
- Sun (est.)
- 4 h/day
- Humidity
- 81 %
For your trip planning
September: warmer, with fewer rainy days than October
Our September series has higher average daily highs and lows than October, fewer rainy days and more sunshine. That favours September for long walks. Compared with August, however, it is cooler with the same rainy-day count. Pack an extra layer for evening walks and keep a rain alternative; monthly averages are not a forecast for your travel dates.
Climate evidence with direct month comparison
The highlighted row is the selected month. Precipitation total and rainy days are separate monthly averages.
| Month | Avg high °C | Avg low °C | Rainy days (est.) | Precipitation mm | Sun h/day (est.) | Humidity % | Wind m/s | Score |
|---|---|---|---|---|---|---|---|---|
| August | 23 | 12 | 11 | 60 | 5.5 | 77 | 3.0 | 79 |
| September (selected) | 20 | 10 | 11 | 55 | 4.0 | 81 | 3.1 | 70 |
| October | 15 | 8 | 13 | 77 | 2.3 | 87 | 3.4 | 47 |
How do the previous and next months compare?
Baseline: September (70/100)
Positive and negative values show the change from the selected month.
| Score Δ | Average high Δ | Average low Δ | Rainy days Δ | Rain Δ | Sun Δ | Humidity Δ | Wind Δ | |
|---|---|---|---|---|---|---|---|---|
| August | +9 | +2.8 °C | +2.2 °C | -0.3 | +4.7 mm | +1.5 h | -4.2 % | -0.1 m/s |
| October | -23 | -4.4 °C | -2.7 °C | +2.1 | +21.6 mm | -1.7 h | +5.8 % | +0.3 m/s |
All twelve months in context
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Where to stay in London
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Useful next decisions
Frequently asked questions
How warm is London in September?
The average daily high is around 20 °C, with an average daily low of about 10 °C.
Does it rain a lot in London in September?
The curated estimate is about 11 rainy days per month, not a directly measured long-term average. Total precipitation averages around 55 mm for the month. A rainy day does not mean all-day rain.
When is the best time to visit London?
By the climate score, June, July, August and September are the strongest months for London. September is one of them.