Month by month
| Month | Afternoon | Sea | Rain | Verdict |
|---|---|---|---|---|
| January | 7.7 °C | — | 12 days | Unfavourable season |
| February | 9.2 °C | — | 11 days | Unfavourable season |
| March | 10.9 °C | — | 13 days | Unfavourable season |
| April | 13.8 °C | — | 10 days | Possible, with trade-offs |
| May | 17.4 °C | — | 11 days | Possible, with trade-offs |
| June | 20.8 °C | — | 11 days | Pleasant — a good time to go |
| July | 22.6 °C | — | 11 days | Pleasant — a good time to go |
| August | 22.3 °C | — | 10 days | Pleasant — a good time to go |
| September | 19.7 °C | — | 11 days | Pleasant — a good time to go |
| October | 15.5 °C | — | 12 days | Possible, with trade-offs |
| November | 11 °C | — | 11 days | Unfavourable season |
| December | 9.3 °C | — | 12 days | Unfavourable season |
Nearby in September
Before you go
Three things to check once you have picked your dates.
Safety
No advisory published for this destination.
Health
CDC level 2 notice: Polio (global)
Vaccines · hepatitis B if you are not already vaccinated; hepatitis A and polio depending on activities and areas visited. Routine vaccines up to date (measles in particular).
Yellow fever · No yellow fever locally, vaccine not recommended. No entry requirement.
Malaria · None.
Per the CDC (page reviewed 25 August 2026); see a travel clinic a few weeks before departure.
Beau Fixe is not a safety or health authority. These notes summarise dated public texts and link to their source: France Diplomatie (Licence Ouverte 2.0), Foreign, Commonwealth & Development Office (gov.uk, Open Government Licence v3.0), Centers for Disease Control and Prevention (Source: CDC). Only the competent authorities are authoritative.
FAQ
Can you swim in London in September?
London is not a seaside destination (no sea data).
How hot is London in September?
Expect 19.7°C in the afternoon and 11.6°C at night, averaged over the last 10 years.
Does it rain a lot in London in September?
Around 11 days with rain (≥ 1 mm) in the month — 37% of days.