2025 Compare Climate & Weather:
Grass Valley, CA vs Boise City, ID

Highlights

On average, there are 206 sunny days per year in Boise City. Grass Valley averages 243 sunny days per year. The US average is 205 sunny days.

Boise City, Idaho gets 13 inches of rain, on average, per year. Grass Valley, California gets 55 inches of rain, on average, per year. The US average is 38.1 inches of rain per year.

Boise City averages 17.5 inches of snow per year. Grass Valley averages 11.3 inches of snow per year. The US average is 27.8 inches of snow per year.

Weather Highlights

Boise City, Idaho
Summer High: the July high is around 91.6 degrees
Winter Low: the January low is 23.7
Rain: averages 13 inches of rain a year
Snow: averages 17.5 inches of snow a year

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

BestPlaces Comfort Index

The annual BestPlaces Comfort Index for Boise is 7.3 (10=best), which means it is one of the most pleasant places in Idaho.

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

Today's Weather - Grass Valley, CA

53°F

Today's Weather - Boise City, ID

46°F

Average Monthly High / Low (°F)

Hot, Freezing, Rainy, Snowy Days: Grass Valley / Boise City

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.

July is the hottest month for Boise with an average high temperature of 91.6°, which ranks it as one of the hottest places in Idaho. In Boise, there are 3 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for Boise are September, June and May.

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

December has the coldest nighttime temperatures for Boise with an average of 22.7°. This is warmer than most places in Idaho.

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 Boise, there are 51.0 days annually when the high temperature is over 90°, which is one of the hottest places in Idaho.

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 Boise, there are 114.9 days annually when the nighttime low temperature falls below freezing, which is one of the warmest places in Idaho.

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.

In Boise, there are 2.8 days annually when the nighttime low temperature falls below zero°, which is warmer than most places in Idaho.

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.


December is the wettest month in Boise with 1.9 inches of rain, and the driest month is July with 0.3 inches. The wettest season is Spring with 35% of yearly precipitation and 10% occurs in Autumn, which is the driest season. The annual rainfall of 13.0 inches in Boise means that it is about average compared to other places in Idaho.

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.

December is the rainiest month in Boise with 11.3 days of rain, and August is the driest month with only 2.3 rainy days. There are 87.0 rainy days annually in Boise, which is less rainy than most places in Idaho. The rainiest season is Spring when it rains 35% of the time and the driest is Autumn with only a 12% chance of a rainy day.

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

An annual snowfall of 17.5 inches in Boise means that it is less snowy than most places in Idaho.

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

December is the snowiest month in Boise with 6.4 inches of snow, and 5 months of the year have significant snowfall.