2025 Compare Climate & Weather:
Herndon, VA vs San Francisco, CA

Highlights

On average, there are 259 sunny days per year in San Francisco. Herndon averages 201 sunny days per year. The US average is 205 sunny days.

San Francisco, California gets 24.6 inches of rain, on average, per year. Herndon, Virginia gets 42.9 inches of rain, on average, per year. The US average is 38.1 inches of rain per year.

San Francisco averages 0 inches of snow per year. Herndon averages 21.5 inches of snow per year. The US average is 27.8 inches of snow per year.

Weather Highlights

San Francisco, California
Summer High: the July high is around 67.2 degrees
Winter Low: the January low is 45.5
Rain: averages 24.6 inches of rain a year
Snow: averages 0 inches of snow a year

Herndon, Virginia
Summer High: the July high is around 85.8 degrees
Winter Low: the January low is 23.5
Rain: averages 42.9 inches of rain a year
Snow: averages 21.5 inches of snow a year

BestPlaces Comfort Index

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

The annual BestPlaces Comfort Index for Herndon is 7.3 (10=best), which means it is about average compared to other places in Virginia.

Today's Weather - Herndon, VA

70°F

Today's Weather - San Francisco, CA

52°F

Average Monthly High / Low (°F)

Hot, Freezing, Rainy, Snowy Days: Herndon / San Francisco

July is the hottest month for Herndon with an average high temperature of 85.8°, which ranks it as cooler than most places in Virginia. In Herndon, there are 4 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for Herndon are September, June and May.

September is the hottest month for San Francisco with an average high temperature of 69.9°, which ranks it as one of the coolest places in California. In San Francisco, there are 0 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for San Francisco are September, October and August.

January has the coldest nighttime temperatures for Herndon with an average of 23.5°. This is colder than most places in Virginia.

January has the coldest nighttime temperatures for San Francisco with an average of 45.5°. This is one of the warmest places in California.

In Herndon, there are 18.9 days annually when the high temperature is over 90°, which is cooler than most places in Virginia.

In San Francisco, there are 1.9 days annually when the high temperature is over 90°, which is one of the coolest places in California.

In Herndon, there are 103.9 days annually when the nighttime low temperature falls below freezing, which is about average compared to other places in Virginia.

In San Francisco, there are 0.3 days annually when the nighttime low temperature falls below freezing, which is one of the warmest places in California.

In Herndon, there are 0.6 days annually when the nighttime low temperature falls below zero°, which is colder than most places in Virginia.

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

May is the wettest month in Herndon with 4.6 inches of rain, and the driest month is February with 2.8 inches. The wettest season is Summer with 28% of yearly precipitation and 21% occurs in Spring, which is the driest season. The annual rainfall of 42.9 inches in Herndon means that it is drier than most places in Virginia.


January is the wettest month in San Francisco with 4.8 inches of rain, and the driest month is July with 0.0 inches. The wettest season is Spring with 57% of yearly precipitation and 1% occurs in Autumn, which is the driest season. The annual rainfall of 24.6 inches in San Francisco means that it is wetter than most places in California.

May is the rainiest month in Herndon with 12.2 days of rain, and October is the driest month with only 8.1 rainy days. There are 119.5 rainy days annually in Herndon, which is rainier than most places in Virginia. The rainiest season is Summer when it rains 28% of the time and the driest is Winter with only a 22% chance of a rainy day.

December is the rainiest month in San Francisco with 11.7 days of rain, and July is the driest month with only 0.6 rainy days. There are 72.3 rainy days annually in San Francisco, which is rainier than most places in California. The rainiest season is Spring when it rains 48% of the time and the driest is Autumn with only a 4% chance of a rainy day.

An annual snowfall of 21.5 inches in Herndon means that it is one of the snowiest places in Virginia.

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

February is the snowiest month in Herndon with 7.8 inches of snow, and 5 months of the year have significant snowfall.

Any measurable snowfall is a rare occurance in San Francisco.