2025 Compare Climate & Weather:
Mill Valley, CA vs Walnut Creek, CA

Highlights

On average, there are 262 sunny days per year in Walnut Creek. Mill Valley averages 255 sunny days per year. The US average is 205 sunny days.

Walnut Creek, California gets 19.6 inches of rain, on average, per year. Mill Valley, California gets 40.6 inches of rain, on average, per year. The US average is 38.1 inches of rain per year.

Walnut Creek averages 0 inches of snow per year. Mill Valley averages 0 inches of snow per year. The US average is 27.8 inches of snow per year.

Weather Highlights

Walnut Creek, California
Summer High: the July high is around 85.8 degrees
Winter Low: the January low is 39.5
Rain: averages 19.6 inches of rain a year
Snow: averages 0 inches of snow a year

Mill Valley, California
Summer High: the July high is around 76.5 degrees
Winter Low: the January low is 42.9
Rain: averages 40.6 inches of rain a year
Snow: averages 0 inches of snow a year

BestPlaces Comfort Index

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

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

Today's Weather - Mill Valley, CA

61°F

Today's Weather - Walnut Creek, CA

67°F

Average Monthly High / Low (°F)

Hot, Freezing, Rainy, Snowy Days: Mill Valley / Walnut Creek

September is the hottest month for Mill Valley with an average high temperature of 76.9°, which ranks it as cooler than most places in California. In Mill Valley, there are 5 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for Mill Valley are September, August and July.

July is the hottest month for Walnut Creek with an average high temperature of 85.8°, which ranks it as cooler than most places in California. In Walnut Creek, there are 5 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for Walnut Creek are May, October and June.

January has the coldest nighttime temperatures for Mill Valley with an average of 42.9°. This is warmer than most places in California.

January has the coldest nighttime temperatures for Walnut Creek with an average of 39.5°. This is warmer than most places in California.

In Mill Valley, there are 12.3 days annually when the high temperature is over 90°, which is cooler than most places in California.

In Walnut Creek, there are 36.5 days annually when the high temperature is over 90°, which is about average compared to other places in California.

In Mill Valley, there are 2.2 days annually when the nighttime low temperature falls below freezing, which is warmer than most places in California.

In Walnut Creek, there are 9.0 days annually when the nighttime low temperature falls below freezing, which is warmer than most places in California.

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

December is the wettest month in Mill Valley with 8.3 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 40.6 inches in Mill Valley means that it is wetter than most places in California.


February is the wettest month in Walnut Creek 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 19.6 inches in Walnut Creek means that it is about average compared to other places in California.

January is the rainiest month in Mill Valley with 12.8 days of rain, and July is the driest month with only 0.9 rainy days. There are 78.1 rainy days annually in Mill Valley, 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 5% chance of a rainy day.

December is the rainiest month in Walnut Creek with 11.1 days of rain, and July is the driest month with only 0.1 rainy days. There are 62.2 rainy days annually in Walnut Creek, which is rainier than most places in California. The rainiest season is Spring when it rains 52% of the time and the driest is Autumn with only a 2% chance of a rainy day.

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

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

Any measurable snowfall is a rare occurance in Mill Valley.

Any measurable snowfall is a rare occurance in Walnut Creek.