Rio Vista, California, gets 15 inches of rain per year. The US average is 37. Snowfall is 0 inches. The average US city gets 25 inches of snow per year. The number of days with any measurable precipitation is 48.
On average, there are 268 sunny days per year in Rio Vista, California. The July high is around 91 degrees. The January low is 37. Our comfort index, which is based on humidity during the hot months, is a 48 out of 100, where higher is more comfortable. The US average on the comfort index is 44.