Avg high
20°C
Avg low
12°C
Rainfall
73 mm
Rain days
11.2
Sunshine
8.6 h/day
Daylight
12.4 h
What to pack for London in September
- t-shirts and light layers
- a light jacket for evenings
- a compact umbrella or rain shell — rain is frequent
Humidity averages 77%; max daily wind around 20 km/h.
How September compares
Best months in London: June–August. See the full best time to visit London guide.
London in September: the details
In September, London sees average daytime highs of 20°C (69°F) and overnight lows of 12°C (53°F). Rainfall totals roughly 73 mm across 11.2 rainy days, and the sun shines about 8.6 hours per day with 12.4 hours of daylight mid-month. Relative humidity averages 77%.
These figures are climate normals computed from the ERA5 weather reanalysis (2019–2024) for London, United Kingdom (51.51, -0.13) — see our methodology. Actual conditions vary year to year.
Where should you go next month?
Get one email a month with the destinations at their seasonal best. Double opt-in, unsubscribe anytime.