2025 Compare Climate & Weather:
Dillon, MT vs Surprise, AZ

Highlights

On average, there are 301 sunny days per year in Surprise. Dillon averages 181 sunny days per year. The US average is 205 sunny days.

Surprise, Arizona gets 9.2 inches of rain, on average, per year. Dillon, Montana gets 10.6 inches of rain, on average, per year. The US average is 38.1 inches of rain per year.

Surprise averages 0.1 inches of snow per year. Dillon averages 20.7 inches of snow per year. The US average is 27.8 inches of snow per year.

Weather Highlights

Surprise, Arizona
Summer High: the July high is around 105.5 degrees
Winter Low: the January low is 42.2
Rain: averages 9.2 inches of rain a year
Snow: averages 0.1 inches of snow a year

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

BestPlaces Comfort Index

The annual BestPlaces Comfort Index for Surprise is 7.3 (10=best), which means it is less comfortable than most places in Arizona.

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

Today's Weather - Dillon, MT

77°F

Today's Weather - Surprise, AZ

98°F

Average Monthly High / Low (°F)

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

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.

July is the hottest month for Surprise with an average high temperature of 105.5°, which ranks it as warmer than most places in Arizona. In Surprise, there are 4 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for Surprise are March, November and April.

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

December has the coldest nighttime temperatures for Surprise with an average of 41.1°. This is warmer than most places in Arizona.

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

In Surprise, there are 165.1 days annually when the high temperature is over 90°, which is hotter than most places in Arizona.

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 Surprise, there are 4.0 days annually when the nighttime low temperature falls below freezing, which is warmer than most places in Arizona.

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.

In Surprise, there are 0.0 days annually when the nighttime low temperature falls below zero°, which is about average compared to other places in Arizona.

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.


February is the wettest month in Surprise with 1.3 inches of rain, and the driest month is May with 0.1 inches. The wettest season is Spring with 37% of yearly precipitation and 15% occurs in Summer, which is the driest season. The annual rainfall of 9.2 inches in Surprise means that it is drier than most places in Arizona.

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.

February is the rainiest month in Surprise with 3.9 days of rain, and June is the driest month with only 0.4 rainy days. There are 32.0 rainy days annually in Surprise, which is less rainy than most places in Arizona. The rainiest season is Spring when it rains 36% of the time and the driest is Summer with only a 19% chance of a rainy day.

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

An annual snowfall of 0.1 inches in Surprise means that it is less snowy than most places in Arizona.

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

December is the snowiest month in Surprise with 0.0 inches of snow, and no months of the year have significant snowfall.