Jefferson County Climate
Jefferson County, Montana
Avg Annual Temp
42.6°F
Annual Precip
10.8"
Annual Snowfall
—
Extreme Heat Days
12
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Seasonal Overview
National Comparison
Climate Profile
About Jefferson County Weather
A dry climate with cool averages
Jefferson County is notably dry, receiving only 10.8 inches of precipitation per year. Its annual average temperature of 42.6°F is roughly 12 degrees below the national median.
Slightly cooler than the state average
With an average of 42.6°F, Jefferson County is just over a degree cooler than the Montana state average of 43.7°F. It ranks among the more arid counties in the state.
Similar to Granite and Judith Basin
Jefferson County's 42.6°F temperature mirrors Granite County (42.5°F) and is slightly cooler than Judith Basin (43.4°F). It is significantly drier than its neighbor, Glacier County.
Mild summers and low heat risk
Summer heat is moderate here, with only 12 days reaching 90°F and a July average of 65.4°F. While snowfall data is limited, winters stay cold with a January average of 23.5°F.
Focus on moisture and winter heat
With only 10.8 inches of precipitation, water-wise landscaping is essential for residents. Heating remains the primary utility concern, as summer cooling needs are minimal with only 12 extreme heat days.
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.