2025 Compare Climate & Weather:
Sunnyvale, CA vs Los Altos, CA

Highlights

On average, there are 263 sunny days per year in Los Altos. Sunnyvale averages 260 sunny days per year. The US average is 205 sunny days.

Los Altos, California gets 18.8 inches of rain, on average, per year. Sunnyvale, California gets 15.4 inches of rain, on average, per year. The US average is 38.1 inches of rain per year.

Los Altos averages 0 inches of snow per year. Sunnyvale averages 0 inches of snow per year. The US average is 27.8 inches of snow per year.

Weather Highlights

Los Altos, California
Summer High: the July high is around 80.9 degrees
Winter Low: the January low is 39.9
Rain: averages 18.8 inches of rain a year
Snow: averages 0 inches of snow a year

Sunnyvale, California
Summer High: the July high is around 80.3 degrees
Winter Low: the January low is 42.3
Rain: averages 15.4 inches of rain a year
Snow: averages 0 inches of snow a year

BestPlaces Comfort Index

The annual BestPlaces Comfort Index for Los Altos is 8.7 (10=best), which means it is more comfortable than most places in California.

The annual BestPlaces Comfort Index for Sunnyvale is 8.8 (10=best), which means it is more comfortable than most places in California.

Today's Weather - Sunnyvale, CA

66°F

Today's Weather - Los Altos, CA

66°F

Average Monthly High / Low (°F)

Hot, Freezing, Rainy, Snowy Days: Sunnyvale / Los Altos

August is the hottest month for Sunnyvale with an average high temperature of 80.3°, which ranks it as cooler than most places in California. In Sunnyvale, there are 6 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for Sunnyvale are June, September and July.

July is the hottest month for Los Altos with an average high temperature of 80.9°, which ranks it as cooler than most places in California. In Los Altos, there are 6 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for Los Altos are June, September and August.

December has the coldest nighttime temperatures for Sunnyvale with an average of 42.2°. This is warmer than most places in California.

December has the coldest nighttime temperatures for Los Altos with an average of 39.7°. This is warmer than most places in California.

In Sunnyvale, there are 13.3 days annually when the high temperature is over 90°, which is cooler than most places in California.

In Los Altos, there are 17.6 days annually when the high temperature is over 90°, which is cooler than most places in California.

In Sunnyvale, there are 2.3 days annually when the nighttime low temperature falls below freezing, which is warmer than most places in California.

In Los Altos, there are 10.4 days annually when the nighttime low temperature falls below freezing, which is warmer than most places in California.

In Sunnyvale, 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 Los Altos, 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 Sunnyvale with 3.1 inches of rain, and the driest month is July with 0.0 inches. The wettest season is Spring with 56% of yearly precipitation and 1% occurs in Autumn, which is the driest season. The annual rainfall of 15.4 inches in Sunnyvale means that it is drier than most places in California.


February is the wettest month in Los Altos with 3.9 inches of rain, and the driest month is July with 0.0 inches. The wettest season is Spring with 58% of yearly precipitation and 1% occurs in Autumn, which is the driest season. The annual rainfall of 18.8 inches in Los Altos means that it is about average compared to other places in California.

December is the rainiest month in Sunnyvale with 10.5 days of rain, and July is the driest month with only 0.2 rainy days. There are 62.6 rainy days annually in Sunnyvale, which is rainier than most places in California. The rainiest season is Spring when it rains 49% of the time and the driest is Autumn with only a 2% chance of a rainy day.

January is the rainiest month in Los Altos with 10.4 days of rain, and July is the driest month with only 0.1 rainy days. There are 60.9 rainy days annually in Los Altos, which is about average compared to other 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.

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

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

Any measurable snowfall is a rare occurance in Sunnyvale.

Any measurable snowfall is a rare occurance in Los Altos.