2025 Compare Climate & Weather:
Casper, WY vs Spearfish, SD

Highlights

On average, there are 227 sunny days per year in Spearfish. Casper averages 220 sunny days per year. The US average is 205 sunny days.

Spearfish, South Dakota gets 21.3 inches of rain, on average, per year. Casper, Wyoming gets 13 inches of rain, on average, per year. The US average is 38.1 inches of rain per year.

Spearfish averages 56.4 inches of snow per year. Casper averages 70.3 inches of snow per year. The US average is 27.8 inches of snow per year.

Weather Highlights

Spearfish, South Dakota
Summer High: the July high is around 87.6 degrees
Winter Low: the January low is 17
Rain: averages 21.3 inches of rain a year
Snow: averages 56.4 inches of snow a year

Casper, Wyoming
Summer High: the July high is around 88.2 degrees
Winter Low: the January low is 15.4
Rain: averages 13 inches of rain a year
Snow: averages 70.3 inches of snow a year

BestPlaces Comfort Index

The annual BestPlaces Comfort Index for Spearfish is 6.9 (10=best), which means it is more comfortable than most places in South Dakota.

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

Today's Weather - Casper, WY

63°F

Today's Weather - Spearfish, SD

70°F

Average Monthly High / Low (°F)

Hot, Freezing, Rainy, Snowy Days: Casper / Spearfish

July is the hottest month for Casper with an average high temperature of 88.2°, which ranks it as warmer than most places in Wyoming. In Casper, there are 2 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for Casper are June, September and August.

July is the hottest month for Spearfish with an average high temperature of 87.6°, which ranks it as warmer than most places in South Dakota. In Spearfish, there are 2 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for Spearfish are June, September and August.

January has the coldest nighttime temperatures for Casper with an average of 15.4°. This is one of the warmest places in Wyoming.

January has the coldest nighttime temperatures for Spearfish with an average of 17.0°. This is one of the warmest places in South Dakota.

In Casper, there are 29.7 days annually when the high temperature is over 90°, which is hotter than most places in Wyoming.

In Spearfish, there are 31.3 days annually when the high temperature is over 90°, which is hotter than most places in South Dakota.

In Casper, there are 168.3 days annually when the nighttime low temperature falls below freezing, which is one of the warmest places in Wyoming.

In Spearfish, there are 144.6 days annually when the nighttime low temperature falls below freezing, which is one of the warmest places in South Dakota.

In Casper, there are 12.5 days annually when the nighttime low temperature falls below zero°, which is warmer than most places in Wyoming.

In Spearfish, there are 12.9 days annually when the nighttime low temperature falls below zero°, which is one of the warmest places in South Dakota.

May is the wettest month in Casper with 2.2 inches of rain, and the driest month is January with 0.5 inches. The wettest season is Summer with 35% of yearly precipitation and 14% occurs in Spring, which is the driest season. The annual rainfall of 13.0 inches in Casper means that it is about average compared to other places in Wyoming.


May is the wettest month in Spearfish with 3.6 inches of rain, and the driest month is January with 0.6 inches. The wettest season is Summer with 34% of yearly precipitation and 9% occurs in Spring, which is the driest season. The annual rainfall of 21.3 inches in Spearfish means that it is drier than most places in South Dakota.

May is the rainiest month in Casper with 10.0 days of rain, and January is the driest month with only 5.0 rainy days. There are 79.2 rainy days annually in Casper, which is rainier than most places in Wyoming. The rainiest season is Summer when it rains 32% of the time and the driest is Spring with only a 20% chance of a rainy day.

June is the rainiest month in Spearfish with 11.7 days of rain, and February is the driest month with only 5.5 rainy days. There are 90.3 rainy days annually in Spearfish, which is one of the rainiest places in South Dakota. The rainiest season is Summer when it rains 30% of the time and the driest is Spring with only a 19% chance of a rainy day.

An annual snowfall of 70.3 inches in Casper means that it is snowier than most places in Wyoming.

An annual snowfall of 56.4 inches in Spearfish means that it is one of the snowiest places in South Dakota.

March is the snowiest month in Casper with 11.5 inches of snow, and 9 months of the year have significant snowfall.

March is the snowiest month in Spearfish with 10.8 inches of snow, and 8 months of the year have significant snowfall.