Average annual temperature is 14.4 °C
Absolute maximum temperature: 39.4 °C
Absolute minimum temperature: 0.1 °C
Number of sunny days: 264 days
Number of rainy days: 101 days
Look at detailed online map of Contra Costa County
* Weather data for Contra Costa County United States is based on climate observations for 2026 year
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Absolute maximum temperature (°C) | 17.5 | 17.5 | 17.9 | 30.5 | 30.4 | 36.1 | 39.4 | 36.4 | 31.3 | 33.4 | 25.5 | 17.8 |
| Average daytime temperature (°C) | 12.6 | 12.5 | 13.1 | 19.4 | 21.4 | 24.7 | 31.8 | 31.6 | 26.5 | 25.0 | 17.9 | 14.6 |
| Average temperature (°C) | 8.4 | 7.7 | 8.2 | 12.4 | 14.3 | 16.5 | 22.1 | 22.4 | 18.7 | 17.9 | 12.9 | 10.4 |
| Average night temperature (°C) | 5.3 | 3.7 | 4.9 | 7.3 | 9.8 | 11.3 | 14.9 | 16.0 | 13.6 | 12.7 | 8.4 | 7.0 |
| Absolute minimum temperature (°C) | 0.9 | 0.1 | 0.1 | 1.0 | 5.9 | 8.3 | 10.5 | 12.4 | 11.2 | 5.1 | 1.4 | 2.5 |
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight maximum duration (h) | 10.0 | 11.0 | 12.0 | 13.0 | 14.0 | 14.0 | 14.0 | 14.0 | 13.0 | 11.0 | 10.0 | 9.0 |
| Daylight mean duration (h) | 9.9 | 10.8 | 12.0 | 13.2 | 14.2 | 14.7 | 14.5 | 13.6 | 12.4 | 11.2 | 10.1 | 9.6 |
| Daylight minimum duration (h) | 9.0 | 10.0 | 11.0 | 12.0 | 13.0 | 14.0 | 14.0 | 13.0 | 11.0 | 10.0 | 9.0 | 9.0 |
| Sunshine mean duration (h) | 5.7 | 7.7 | 7.8 | 11.3 | 11.4 | 13.0 | 13.2 | 12.3 | 10.8 | 9.5 | 8.2 | 6.2 |
| Precipitation (mm) | 259 | 79 | 218 | 2 | 28 | 0 | 0 | 1 | 2 | 10 | 47 | 108 |
| Sunny days | 12 | 16 | 10 | 26 | 21 | 30 | 31 | 28 | 27 | 25 | 22 | 16 |
| Rainy days | 19 | 12 | 21 | 4 | 10 | 0 | 0 | 3 | 3 | 6 | 8 | 15 |
| Snow days | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
The best time to visit Contra Costa County during the most sunny months:
The largest precipitation sum in Contra Costa County is at