Custer County Climate
Custer County, Montana
Avg Annual Temp
46.4°F
Annual Precip
14.1"
Annual Snowfall
29.9"
Extreme Heat Days
44.06666666666666
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Seasonal Overview
National Comparison
Climate Profile
About Custer County Weather
A warmer pocket in a cold state
Custer County maintains an annual average temperature of 46.4°F, which sits well below the national median but remains notably warm for the Northern Rockies. The region experiences a semi-arid climate characterized by low humidity and 14.1 inches of annual precipitation.
Leading the state in heat
With an average temperature 2.7°F higher than the Montana state average of 43.7°F, Custer ranks as one of the state's warmer jurisdictions. It receives slightly less moisture than the state average of 15.4 inches, defining it as a dry, temperate outlier.
Competing with eastern neighbors
Custer’s climate mirrors Dawson County to the northeast, which is slightly warmer at 46.6°F. However, it is significantly warmer than Fallon County, where the average temperature drops to 44.0°F.
Sweltering summers and moderate snow
Residents face 44 days of extreme heat above 90°F, a high frequency for Montana, while July averages reach 74.0°F. Winter brings a manageable 29.9 inches of snow, much lower than the heavy totals found in the western mountains.
Preparing for the heat
Because summer temperatures frequently spike, high-efficiency cooling systems are a priority for local homeowners. Gardeners should prioritize drought-resistant plants to accommodate the low 14.1-inch annual rainfall.
Frequently Asked Questions
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Data source: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020.
Climate normals are 30-year averages of weather variables computed from 1991 to 2020. Station data is aggregated to county level using spatial averaging. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.