The climate in Castro Valley, CA is generally mild with mild winters and warm summers. Temperatures rarely fall below freezing during the winter months, and summer temperatures usually reach into the high 80s. Precipitation is spread throughout the year with an average of 36 inches annually. The area is typically sunny most days of the year, but the spring and summer months tend to be a bit more humid than the rest of the year.
Castro Valley, California gets 21 inches of rain, on average, per year. The US average is 38 inches of rain per year.
Castro Valley averages 0 inches of snow per year. The US average is 28 inches of snow per year.
On average, there are 261 sunny days per year in Castro Valley. The US average is 205 sunny days.
Castro Valley gets some kind of precipitation, on average, 66 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 76 degrees
Winter Low: the January low is 42
Rain: averages 21 inches of rain a year
Snow: averages 0 inches of snow a year