Average annual temperature is 10.9 °C
Absolute maximum temperature: 29.3 °C
Absolute minimum temperature: -5.6 °C
Number of sunny days: 127 days
Number of rainy days: 238 days
Look at detailed online map of Harwell
* Weather data for Harwell United Kingdom is based on climate observations for 2026 year
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Absolute maximum temperature (°C) | 12.2 | 12.3 | 13.9 | 16.9 | 20.8 | 27.6 | 26.0 | 25.2 | 29.3 | 22.7 | 14.4 | 12.5 |
| Average daytime temperature (°C) | 7.3 | 9.0 | 9.6 | 12.0 | 16.5 | 22.5 | 19.6 | 20.2 | 21.6 | 15.7 | 9.9 | 9.1 |
| Average temperature (°C) | 4.4 | 5.5 | 6.7 | 8.0 | 12.1 | 17.3 | 16.1 | 16.3 | 17.1 | 12.3 | 7.2 | 7.1 |
| Average night temperature (°C) | 1.4 | 2.3 | 3.8 | 3.8 | 7.7 | 11.8 | 12.3 | 12.2 | 12.7 | 9.4 | 4.4 | 4.8 |
| Absolute minimum temperature (°C) | -5.6 | -3.8 | -2.8 | -2.1 | 4.6 | 6.2 | 8.4 | 9.6 | 7.3 | 1.2 | -3.0 | -3.9 |
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight maximum duration (h) | 9.0 | 10.0 | 12.0 | 14.0 | 16.0 | 16.0 | 16.0 | 15.0 | 13.0 | 11.0 | 9.0 | 8.0 |
| Daylight mean duration (h) | 8.4 | 10.0 | 11.9 | 13.9 | 15.6 | 16.6 | 16.1 | 14.6 | 12.7 | 10.7 | 8.9 | 7.9 |
| Daylight minimum duration (h) | 7.0 | 9.0 | 10.0 | 12.0 | 14.0 | 16.0 | 15.0 | 13.0 | 11.0 | 9.0 | 8.0 | 7.0 |
| Sunshine mean duration (h) | 4.3 | 4.8 | 4.3 | 7.6 | 10.6 | 12.3 | 9.6 | 10.1 | 8.1 | 6.3 | 4.4 | 2.3 |
| Precipitation (mm) | 68 | 8 | 131 | 67 | 49 | 47 | 86 | 68 | 66 | 113 | 82 | 96 |
| Sunny days | 16 | 18 | 4 | 7 | 14 | 17 | 3 | 7 | 11 | 10 | 10 | 10 |
| Rainy days | 15 | 10 | 27 | 23 | 17 | 13 | 28 | 24 | 19 | 21 | 20 | 21 |
| Snow days | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
The best time to visit Harwell during the most sunny months:
Months with the longest average daylight duration in Harwell:
The largest precipitation sum in Harwell is at