2025 Compare Climate & Weather:
San Ramon, CA vs Rio Vista, CA

Highlights

On average, there are 268 sunny days per year in Rio Vista. San Ramon averages 256 sunny days per year. The US average is 205 sunny days.

Rio Vista, California gets 20.3 inches of rain, on average, per year. San Ramon, California gets 19 inches of rain, on average, per year. The US average is 38.1 inches of rain per year.

Rio Vista averages 0 inches of snow per year. San Ramon averages 0 inches of snow per year. The US average is 27.8 inches of snow per year.

Weather Highlights

Rio Vista, California
Summer High: the July high is around 91.2 degrees
Winter Low: the January low is 38.6
Rain: averages 20.3 inches of rain a year
Snow: averages 0 inches of snow a year

San Ramon, California
Summer High: the July high is around 84.4 degrees
Winter Low: the January low is 39.2
Rain: averages 19 inches of rain a year
Snow: averages 0 inches of snow a year

BestPlaces Comfort Index

The annual BestPlaces Comfort Index for Rio Vista is 8.4 (10=best), which means it is more comfortable than most places in California.

The annual BestPlaces Comfort Index for San Ramon is 8.5 (10=best), which means it is more comfortable than most places in California.

Today's Weather - San Ramon, CA

78°F

Today's Weather - Rio Vista, CA

82°F

Average Monthly High / Low (°F)

Hot, Freezing, Rainy, Snowy Days: San Ramon / Rio Vista

July is the hottest month for San Ramon with an average high temperature of 84.4°, which ranks it as cooler than most places in California. In San Ramon, there are 6 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for San Ramon are June, October and May.

July is the hottest month for Rio Vista with an average high temperature of 91.2°, which ranks it as about average compared to other places in California. In Rio Vista, there are 3 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for Rio Vista are October, May and April.

January has the coldest nighttime temperatures for San Ramon with an average of 39.2°. This is warmer than most places in California.

December has the coldest nighttime temperatures for Rio Vista with an average of 38.5°. This is about average compared to other places in California.

In San Ramon, there are 35.4 days annually when the high temperature is over 90°, which is cooler than most places in California.

In Rio Vista, there are 61.2 days annually when the high temperature is over 90°, which is about average compared to other places in California.

In San Ramon, there are 11.1 days annually when the nighttime low temperature falls below freezing, which is warmer than most places in California.

In Rio Vista, there are 11.2 days annually when the nighttime low temperature falls below freezing, which is warmer than most places in California.

In San Ramon, there are 0.0 days annually when the nighttime low temperature falls below zero°, which is about average compared to other places in California.

In Rio Vista, there are 0.0 days annually when the nighttime low temperature falls below zero°, which is about average compared to other places in California.

February is the wettest month in San Ramon with 3.5 inches of rain, and the driest month is July with 0.0 inches. The wettest season is Spring with 55% of yearly precipitation and 1% occurs in Autumn, which is the driest season. The annual rainfall of 19.0 inches in San Ramon means that it is about average compared to other places in California.


December is the wettest month in Rio Vista with 4.0 inches of rain, and the driest month is July with 0.0 inches. The wettest season is Spring with 59% of yearly precipitation and 0% occurs in Autumn, which is the driest season. The annual rainfall of 20.3 inches in Rio Vista means that it is about average compared to other places in California.

December is the rainiest month in San Ramon with 10.9 days of rain, and July is the driest month with only 0.2 rainy days. There are 64.2 rainy days annually in San Ramon, which is rainier than most places in California. The rainiest season is Spring when it rains 50% of the time and the driest is Autumn with only a 2% chance of a rainy day.

January is the rainiest month in Rio Vista with 10.8 days of rain, and July is the driest month with only 0.0 rainy days. There are 57.9 rainy days annually in Rio Vista, which is about average compared to other places in California. The rainiest season is Spring when it rains 51% of the time and the driest is Autumn with only a 2% chance of a rainy day.

There is rarely any recorded snowfall in San Ramon, ranking it as one of the least snowy places in California.

There is rarely any recorded snowfall in Rio Vista, ranking it as one of the least snowy places in California.

Any measurable snowfall is a rare occurance in San Ramon.

Any measurable snowfall is a rare occurance in Rio Vista.