2025 Compare Climate & Weather:
San Luis Obispo, CA vs Grass Valley, CA

Highlights

On average, there are 243 sunny days per year in Grass Valley. San Luis Obispo averages 287 sunny days per year. The US average is 205 sunny days.

Grass Valley, California gets 55 inches of rain, on average, per year. San Luis Obispo, California gets 20 inches of rain, on average, per year. The US average is 38.1 inches of rain per year.

Grass Valley averages 11.3 inches of snow per year. San Luis Obispo averages 0 inches of snow per year. The US average is 27.8 inches of snow per year.

Weather Highlights

Grass Valley, California
Summer High: the July high is around 87.2 degrees
Winter Low: the January low is 34.2
Rain: averages 55 inches of rain a year
Snow: averages 11.3 inches of snow a year

San Luis Obispo, California
Summer High: the July high is around 73.7 degrees
Winter Low: the January low is 42.8
Rain: averages 20 inches of rain a year
Snow: averages 0 inches of snow a year

BestPlaces Comfort Index

The annual BestPlaces Comfort Index for Grass Valley is 7.9 (10=best), which means it is less comfortable than most places in California.

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

Today's Weather - San Luis Obispo, CA

67°F

Today's Weather - Grass Valley, CA

72°F

Average Monthly High / Low (°F)

Hot, Freezing, Rainy, Snowy Days: San Luis Obispo / Grass Valley

September is the hottest month for San Luis Obispo with an average high temperature of 75.3°, which ranks it as one of the coolest places in California. In San Luis Obispo, there are 5 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for San Luis Obispo are September, August and July.

July is the hottest month for Grass Valley with an average high temperature of 87.2°, which ranks it as about average compared to other places in California. In Grass Valley, there are 4 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for Grass Valley are June, September and May.

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

December has the coldest nighttime temperatures for Grass Valley with an average of 34.0°. This is colder than most places in California.

In San Luis Obispo, there are 6.3 days annually when the high temperature is over 90°, which is cooler than most places in California.

In Grass Valley, there are 28.3 days annually when the high temperature is over 90°, which is cooler than most places in California.

In San Luis Obispo, there are 3.5 days annually when the nighttime low temperature falls below freezing, which is warmer than most places in California.

In Grass Valley, there are 45.7 days annually when the nighttime low temperature falls below freezing, which is colder than most places in California.

In San Luis Obispo, 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 Grass 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.

February is the wettest month in San Luis Obispo with 4.2 inches of rain, and the driest month is July with 0.0 inches. The wettest season is Spring with 59% of yearly precipitation and 1% occurs in Autumn, which is the driest season. The annual rainfall of 20.0 inches in San Luis Obispo means that it is about average compared to other places in California.


December is the wettest month in Grass Valley with 10.4 inches of rain, and the driest month is July with 0.0 inches. The wettest season is Spring with 53% of yearly precipitation and 2% occurs in Autumn, which is the driest season. The annual rainfall of 55.0 inches in Grass Valley means that it is one of the wettest places in California.

February is the rainiest month in San Luis Obispo with 9.2 days of rain, and July is the driest month with only 0.4 rainy days. There are 50.5 rainy days annually in San Luis Obispo, which is about average compared to other places in California. The rainiest season is Spring when it rains 49% of the time and the driest is Autumn with only a 3% chance of a rainy day.

January is the rainiest month in Grass Valley with 12.7 days of rain, and July is the driest month with only 0.3 rainy days. There are 83.8 rainy days annually in Grass Valley, which is one of the rainiest places in California. The rainiest season is Spring when it rains 44% of the time and the driest is Autumn with only a 4% chance of a rainy day.

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

An annual snowfall of 11.3 inches in Grass Valley means that it is snowier than most places in California.

Any measurable snowfall is a rare occurance in San Luis Obispo.

February is the snowiest month in Grass Valley with 3.7 inches of snow, and 6 months of the year have significant snowfall.