Contra Costa, CA County has a Mediterranean climate with warm, dry summers and mild, wet winters. Average temperatures range from the mid-50s to the high-70s in the summer months while winter temperatures rarely drop below freezing. Rainfall is generally concentrated in the winter months, with most of California’s notorious thunderstorms coming through in late spring and early summer. The temperature typically remains moderate and comfortable year round, making it an ideal place for outdoor activities like hiking and camping throughout much of the year.
Contra Costa County, California gets 21 inches of rain, on average, per year. The US average is 38 inches of rain per year.
Contra Costa County averages 0 inches of snow per year. The US average is 28 inches of snow per year.
On average, there are 260 sunny days per year in Contra Costa County. The US average is 205 sunny days.
Contra Costa County gets some kind of precipitation, on average, 62 days per year. Precipitation is rain, snow, sleet, or hail that falls to the ground. In order for precipitation to be counted you have to get at least .01 inches on the ground to measure.
Weather Highlights
Summer High: the July high is around 84 degrees
Winter Low: the January low is 40
Rain: averages 21 inches of rain a year
Snow: averages 0 inches of snow a year