Climate change in Contra Costa County, California
Since 1979, Contra Costa County, California has warmed 1.9°F, with 15 more days above 90°F, 3 more nights above 70°F and 20% less precipitation a year.
- Average temperature: +1.9°F
- Summer highs (Jun–Aug): +2.9°F
- Winter lows (Dec–Feb): +1.9°F
- Precipitation: −20%
- Wettest day of the year: −12%
- Longest dry spell: +28 days
- Days above 90°F: +15 days
- Nights above 70°F: +3 days
- Freezing nights: −4 days
- Frost-free season: +19 days
- Muggy days: +0 days
- Summer heat index (Jun–Aug): +2.8°F
- Extreme fire-weather days: +22 days
Changes follow the trend line through every year from 1979 to 2025. Data: NOAA nClimGrid-Daily; humidity from gridMET, adjusted to airport observations.