2025 Compare Climate & Weather:
San Diego, CA vs Helena, MT

Highlights

On average, there are 189 sunny days per year in Helena. San Diego averages 266 sunny days per year. The US average is 205 sunny days.

Helena, Montana gets 12.6 inches of rain, on average, per year. San Diego, California gets 11.7 inches of rain, on average, per year. The US average is 38.1 inches of rain per year.

Helena averages 42.1 inches of snow per year. San Diego averages 0 inches of snow per year. The US average is 27.8 inches of snow per year.

Weather Highlights

Helena, Montana
Summer High: the July high is around 83.4 degrees
Winter Low: the January low is 13.8
Rain: averages 12.6 inches of rain a year
Snow: averages 42.1 inches of snow a year

San Diego, California
Summer High: the July high is around 78.5 degrees
Winter Low: the January low is 45.6
Rain: averages 11.7 inches of rain a year
Snow: averages 0 inches of snow a year

BestPlaces Comfort Index

The annual BestPlaces Comfort Index for Helena is 6.6 (10=best), which means it is about average compared to other places in Montana.

The annual BestPlaces Comfort Index for San Diego is 9.2 (10=best), which means it is one of the most pleasant places in California.

Today's Weather - San Diego, CA

62°F

Today's Weather - Helena, MT

58°F

Average Monthly High / Low (°F)

Hot, Freezing, Rainy, Snowy Days: San Diego / Helena

August is the hottest month for San Diego with an average high temperature of 80.2°, which ranks it as cooler than most places in California. In San Diego, there are 7 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for San Diego are July, September and August.

July is the hottest month for Helena with an average high temperature of 83.4°, which ranks it as cooler than most places in Montana. In Helena, there are 4 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for Helena are June, August and July.

December has the coldest nighttime temperatures for San Diego with an average of 45.3°. This is one of the warmest places in California.

December has the coldest nighttime temperatures for Helena with an average of 13.6°. This is about average compared to other places in Montana.

In San Diego, there are 13.4 days annually when the high temperature is over 90°, which is cooler than most places in California.

In Helena, there are 15.5 days annually when the high temperature is over 90°, which is cooler than most places in Montana.

In San Diego, there are 0.7 days annually when the nighttime low temperature falls below freezing, which is one of the warmest places in California.

In Helena, there are 170.2 days annually when the nighttime low temperature falls below freezing, which is warmer than most places in Montana.

In San Diego, 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 Helena, there are 16.6 days annually when the nighttime low temperature falls below zero°, which is about average compared to other places in Montana.

February is the wettest month in San Diego with 2.5 inches of rain, and the driest month is August with 0.0 inches. The wettest season is Spring with 55% of yearly precipitation and 2% occurs in Autumn, which is the driest season. The annual rainfall of 11.7 inches in San Diego means that it is drier than most places in California.


June is the wettest month in Helena with 2.1 inches of rain, and the driest month is January with 0.4 inches. The wettest season is Autumn with 37% of yearly precipitation and 10% occurs in Spring, which is the driest season. The annual rainfall of 12.6 inches in Helena means that it is drier than most places in Montana.

February is the rainiest month in San Diego with 6.8 days of rain, and August is the driest month with only 0.4 rainy days. There are 38.4 rainy days annually in San Diego, which is less rainy 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.

May is the rainiest month in Helena with 11.0 days of rain, and February is the driest month with only 5.5 rainy days. There are 89.6 rainy days annually in Helena, which is about average compared to other places in Montana. The rainiest season is Summer when it rains 29% of the time and the driest is Spring with only a 21% chance of a rainy day.

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

An annual snowfall of 42.1 inches in Helena means that it is about average compared to other places in Montana.

Any measurable snowfall is a rare occurance in San Diego.

March is the snowiest month in Helena with 7.4 inches of snow, and 9 months of the year have significant snowfall.