2025 Compare Climate & Weather:
Petaluma, CA vs Dillon, MT

Highlights

On average, there are 181 sunny days per year in Dillon. Petaluma averages 260 sunny days per year. The US average is 205 sunny days.

Dillon, Montana gets 10.6 inches of rain, on average, per year. Petaluma, California gets 29.8 inches of rain, on average, per year. The US average is 38.1 inches of rain per year.

Dillon averages 20.7 inches of snow per year. Petaluma averages 0 inches of snow per year. The US average is 27.8 inches of snow per year.

Weather Highlights

Dillon, Montana
Summer High: the July high is around 83.4 degrees
Winter Low: the January low is 12.2
Rain: averages 10.6 inches of rain a year
Snow: averages 20.7 inches of snow a year

Petaluma, California
Summer High: the July high is around 83.7 degrees
Winter Low: the January low is 38.7
Rain: averages 29.8 inches of rain a year
Snow: averages 0 inches of snow a year

BestPlaces Comfort Index

The annual BestPlaces Comfort Index for Dillon is 6.8 (10=best), which means it is more comfortable than most places in Montana.

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

Today's Weather - Petaluma, CA

51°F

Today's Weather - Dillon, MT

53°F

Average Monthly High / Low (°F)

Hot, Freezing, Rainy, Snowy Days: Petaluma / Dillon

August is the hottest month for Petaluma with an average high temperature of 83.7°, which ranks it as cooler than most places in California. In Petaluma, there are 6 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for Petaluma are October, June and May.

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

December has the coldest nighttime temperatures for Petaluma with an average of 38.3°. This is about average compared to other places in California.

December has the coldest nighttime temperatures for Dillon with an average of 10.5°. This is colder than most places in Montana.

In Petaluma, there are 28.1 days annually when the high temperature is over 90°, which is cooler than most places in California.

In Dillon, there are 10.2 days annually when the high temperature is over 90°, which is cooler than most places in Montana.

In Petaluma, there are 16.7 days annually when the nighttime low temperature falls below freezing, which is about average compared to other places in California.

In Dillon, there are 198.4 days annually when the nighttime low temperature falls below freezing, which is colder than most places in Montana.

In Petaluma, 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 Dillon, there are 17.2 days annually when the nighttime low temperature falls below zero°, which is about average compared to other places in Montana.

December is the wettest month in Petaluma with 5.7 inches of rain, and the driest month is July with 0.0 inches. The wettest season is Spring with 57% of yearly precipitation and 1% occurs in Autumn, which is the driest season. The annual rainfall of 29.8 inches in Petaluma means that it is wetter than most places in California.


May is the wettest month in Dillon with 2.0 inches of rain, and the driest month is February with 0.2 inches. The wettest season is Autumn with 39% of yearly precipitation and 8% occurs in Spring, which is the driest season. The annual rainfall of 10.6 inches in Dillon means that it is one of the driest places in Montana.

January is the rainiest month in Petaluma with 12.5 days of rain, and July is the driest month with only 0.2 rainy days. There are 74.8 rainy days annually in Petaluma, which is rainier than most places in California. The rainiest season is Spring when it rains 49% of the time and the driest is Autumn with only a 2% chance of a rainy day.

May is the rainiest month in Dillon with 10.1 days of rain, and January is the driest month with only 3.2 rainy days. There are 69.8 rainy days annually in Dillon, which is less rainy than most places in Montana. The rainiest season is Summer when it rains 33% of the time and the driest is Spring with only a 15% chance of a rainy day.

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

An annual snowfall of 20.7 inches in Dillon means that it is one of the least snowy places in Montana.

Any measurable snowfall is a rare occurance in Petaluma.

December is the snowiest month in Dillon with 3.6 inches of snow, and 8 months of the year have significant snowfall.