2025 Compare Climate & Weather:
South San Francisco, CA vs Seattle, WA

Highlights

On average, there are 152 sunny days per year in Seattle. South San Francisco averages 259 sunny days per year. The US average is 205 sunny days.

Seattle, Washington gets 38 inches of rain, on average, per year. South San Francisco, California gets 21.7 inches of rain, on average, per year. The US average is 38.1 inches of rain per year.

Seattle averages 4.6 inches of snow per year. South San Francisco averages 0 inches of snow per year. The US average is 27.8 inches of snow per year.

Weather Highlights

Seattle, Washington
Summer High: the July high is around 75.8 degrees
Winter Low: the January low is 37
Rain: averages 38 inches of rain a year
Snow: averages 4.6 inches of snow a year

South San Francisco, California
Summer High: the July high is around 66.7 degrees
Winter Low: the January low is 45
Rain: averages 21.7 inches of rain a year
Snow: averages 0 inches of snow a year

BestPlaces Comfort Index

The annual BestPlaces Comfort Index for Seattle is 7.5 (10=best), which means it is one of the most pleasant places in Washington.

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

Today's Weather - South San Francisco, CA

54°F

Today's Weather - Seattle, WA

46°F

Average Monthly High / Low (°F)

Hot, Freezing, Rainy, Snowy Days: South San Francisco / Seattle

September is the hottest month for South San Francisco with an average high temperature of 69.3°, which ranks it as one of the coolest places in California. In South San Francisco, there are 0 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for South San Francisco are September, October and August.

August is the hottest month for Seattle with an average high temperature of 76.3°, which ranks it as cooler than most places in Washington. In Seattle, there are 4 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for Seattle are August, July and September.

January has the coldest nighttime temperatures for South San Francisco with an average of 45.0°. This is one of the warmest places in California.

December has the coldest nighttime temperatures for Seattle with an average of 35.9°. This is one of the warmest places in Washington.

In South San Francisco, there are 1.8 days annually when the high temperature is over 90°, which is one of the coolest places in California.

In Seattle, there are 1.7 days annually when the high temperature is over 90°, which is cooler than most places in Washington.

In South 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 Seattle, there are 24.0 days annually when the nighttime low temperature falls below freezing, which is one of the warmest places in Washington.

In South 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.

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

January is the wettest month in South San Francisco with 4.3 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 21.7 inches in South San Francisco means that it is wetter than most places in California.


November is the wettest month in Seattle with 6.2 inches of rain, and the driest month is July with 0.8 inches. The wettest season is Spring with 39% of yearly precipitation and 9% occurs in Autumn, which is the driest season. The annual rainfall of 38.0 inches in Seattle means that it is about average compared to other places in Washington.

December is the rainiest month in South San Francisco with 11.4 days of rain, and July is the driest month with only 0.2 rainy days. There are 68.4 rainy days annually in South San Francisco, 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 3% chance of a rainy day.

November is the rainiest month in Seattle with 18.7 days of rain, and August is the driest month with only 5.3 rainy days. There are 155.3 rainy days annually in Seattle, which is about average compared to other places in Washington. The rainiest season is Spring when it rains 33% of the time and the driest is Autumn with only a 13% chance of a rainy day.

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

An annual snowfall of 4.6 inches in Seattle means that it is about average compared to other places in Washington.

Any measurable snowfall is a rare occurance in South San Francisco.

December is the snowiest month in Seattle with 2.1 inches of snow, and 4 months of the year have significant snowfall.