Climate change in Alameda County, California
Since 1979, Alameda County, California has warmed 1.7°F, with 11 more days above 90°F, 2 more nights above 70°F and 19% less precipitation a year. Its climate in 1996–2025 is most like Contra Costa County, CA's was in 1951–1980.
- Average temperature: +1.7°F
- Summer highs (Jun–Aug): +2.7°F
- Winter lows (Dec–Feb): +1.3°F
- Precipitation: −19%
- Wettest day of the year: −9%
- Longest dry spell: +48 days
- Days above 90°F: +11 days
- Nights above 70°F: +2 days
- Freezing nights: −2 days
- Frost-free season: +12 days
- Muggy days: +0 days
- Summer heat index (Jun–Aug): +2.6°F
- Extreme fire-weather days: +29 days
Changes follow the trend line through every year from 1979 to 2025. Data: NOAA nClimGrid-Daily; humidity from gridMET, adjusted to airport observations.