🇬🇧 Weather in London in September
This is what the weather in London (United Kingdom) was like in September in 2017–2026.
Key facts at a glance
Avg. daytime high
20.8 °C
18.7 °C – 23.6 °C
Avg. night-time low
10.8 °C
9.4 °C – 13.4 °C
Avg. rain days in period
11.1
37 % of days · ≥ 1.0 mm
Avg. precipitation in period
51.4 mm
22.9 mm – 91.2 mm
Avg. sunshine per day
n/a
Sunshine duration is not available from this data source.
Avg. sea temperature
–
No sea nearby – no sea temperature.
Extremes: Highest temperature 31.1 °C (9 Sep 2023) · Lowest temperature 4.2 °C (24 Sep 2018) · Avg. daily peak wind 24 km/h
Weather mix of all days
- 26Sunny
- 77Partly cloudy
- 61Cloudy
- 81Light rain
- 30Rain
Summary
- On average 20.8 °C during the day and 10.8 °C at night.
- On average 11.1 rain days (Rain day = at least 1.0 mm of precipitation) with 51.4 mm of precipitation in total.
- Prevailing: Light rain.
- Warmest year: 2026 (avg. 23.6 °C), coolest: 2017 (avg. 18.7 °C).
- Wettest year: 2024 (91.2 mm), driest: 2026 (22.9 mm).
- Extremes: 31.1 °C on 9 Sep 2023 and 4.2 °C on 24 Sep 2018.
Overall values from all 10 years. How is this calculated?
Charts
Temperatures per year
Average over your travel period
Precipitation & rain days
Year by year
2026
Avg. max23.6°Avg. min12.4°- Rain days
- 5 Rain days
- Precipitation
- 22.9 mm
- Avg. sunshine per day
- n/a
- Sea temperature
- –
Max 27.2 °C · Min 9.3 °C
2025
Avg. max20.2°Avg. min10.4°- Rain days
- 11 Rain days
- Precipitation
- 42.6 mm
- Avg. cloud cover
- 56 % cloudy
- Sea temperature
- –
Max 26.7 °C · Min 5.4 °C
2024
Avg. max19.7°Avg. min10.8°- Rain days
- 18 Rain days
- Precipitation
- 91.2 mm
- Avg. cloud cover
- 72 % cloudy
- Sea temperature
- –
Max 27.0 °C · Min 4.4 °C
2023
Avg. max23.4°Avg. min13.4°- Rain days
- 10 Rain days
- Precipitation
- 41.4 mm
- Avg. cloud cover
- 67 % cloudy
- Sea temperature
- –
Max 31.1 °C · Min 8.0 °C
2022
Avg. max20.1°Avg. min10.8°- Rain days
- 12 Rain days
- Precipitation
- 57.5 mm
- Avg. cloud cover
- 77 % cloudy
- Sea temperature
- –
Max 25.2 °C · Min 5.1 °C
2021
Avg. max21.4°Avg. min11.6°- Rain days
- 10 Rain days
- Precipitation
- 46.0 mm
- Avg. cloud cover
- 68 % cloudy
- Sea temperature
- –
Max 27.2 °C · Min 5.9 °C
2020
Avg. max20.6°Avg. min10.1°- Rain days
- 7 Rain days
- Precipitation
- 43.6 mm
- Avg. cloud cover
- 57 % cloudy
- Sea temperature
- –
Max 26.7 °C · Min 5.1 °C
2019
Avg. max20.3°Avg. min10.0°- Rain days
- 12 Rain days
- Precipitation
- 75.9 mm
- Avg. cloud cover
- 59 % cloudy
- Sea temperature
- –
Max 25.5 °C · Min 5.7 °C
2018
Avg. max19.9°Avg. min9.5°- Rain days
- 7 Rain days
- Precipitation
- 37.9 mm
- Avg. cloud cover
- 63 % cloudy
- Sea temperature
- –
Max 24.2 °C · Min 4.2 °C
2017
Avg. max18.7°Avg. min9.4°- Rain days
- 19 Rain days
- Precipitation
- 55.5 mm
- Avg. cloud cover
- 76 % cloudy
- Sea temperature
- –
Max 22.8 °C · Min 5.1 °C
Frequently asked questions
- How warm is it in London in September?
- Daytime highs averaged 20.8 °C, night-time lows 10.8 °C. The highest value of the past 10 years was 31.1 °C (9 Sep 2023), the lowest 4.2 °C (24 Sep 2018).
- How often does it rain in London in September?
- On average there were 11.1 rain days (at least 1 mm) with 51.4 mm of precipitation in total.
Check your exact travel dates
Choose your travel period – we show the weather for exactly those days.
Other destinations in September
Data sources
- Weather data
- Data obtained from the NASA Langley Research Center (LaRC) POWER Project funded through the NASA Earth Science/Applied Science Program
Reanalysis (weather model constrained by observations) on a coarse grid of about 50 km. Values represent a large area and can differ from local conditions, especially on islands, coasts and in mountains. No sunshine duration.
Reanalysis (weather model constrained by observations)
Reanalysis values represent a grid cell (approx. 25–50 km) and may differ from local measurements on coasts, islands and in mountains. - Sea temperature
- MUR SST data were provided by JPL under support by NASA MEaSUREs program; accessed via NOAA CoastWatch ERDDAP
Daily multi-scale ultra-high resolution (≈ 1 km) analysis of satellite measurements (infrared, microwave) and in-situ data. Represents the foundation temperature below the daily warm surface layer. (Satellite and in-situ analysis) - Place search
- Natural Earth (public domain) · GeoNames (CC BY 4.0) / OpenStreetMap (ODbL)