Jefferson County Climate
Jefferson County, Wisconsin
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
46.9°F
Annual Precip
37.2"
Annual Snowfall
40.1"
Extreme Heat Days
10
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
5b
Minimum winter temperature range for plant survival
2,685
Supports most vegetables & fruits
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Jefferson County
Climate Verdict
Jefferson County has a cool, averaging 46.9°F annually, moderate rainfall of 37.2 inches per year, rare extreme heat with only 10.114285714285714 days above 90°F annually, moderate snowfall of 40.1 inches annually. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are very cold — January averages 19.0°F. summers are warm — July averages 71.8°F. Residents experience a substantial 53°F difference between winter and summer.
Outdoor & Gardening Guidance
Winter sports enthusiasts benefit from reliable snow cover for 3-4 months annually.
Regional Context
Jefferson County closely matches the Wisconsin statewide average temperature of 44.4°F, it is somewhat wetter than average for Wisconsin.
Climate Profile
About Jefferson County Weather
Milder than the Northern Median
Jefferson County averages 46.9°F annually, staying well below the national median of 53.8°F. However, it is one of the warmer spots in the Upper Midwest region.
Warmer than the State Average
At 46.9°F, the county is 2.5 degrees warmer than the 44.4°F Wisconsin average. This makes it one of the more temperate locations for agriculture and residency in the state.
Middle Ground of Southern Wisconsin
Jefferson is slightly cooler than Kenosha County's 48.3°F but warmer than Iowa County's 45.7°F. Its 37.2 inches of rain exceeds the state average of 34.5 inches.
Steamy Summers and Snowy Winters
July averages a warm 71.8°F with 10 days of extreme heat reaching 90°F or higher. Winters are slightly milder than northern neighbors, averaging 22.3°F with 40.1 inches of snow.
Cooling and Drainage Focus
Effective air conditioning is recommended for the 10 annual extreme heat days. Homeowners should also ensure proper yard drainage to manage the 37.2 inches of annual precipitation.
Frequently Asked Questions
What is the average temperature in Jefferson County?
How much rain does Jefferson County get?
Does it snow in Jefferson County?
How hot does Jefferson County get in summer?
How cold are winters in Jefferson County?
Track your own weather in Jefferson County
Ambient Weather personal weather stations give you hyperlocal climate data.
Sponsored
Data sources: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020. Forecast and alert data from National Weather Service API. Air quality data from Open-Meteo.
Climate normals are 30-year averages of weather variables. Station data is aggregated to county level. Forecasts and alerts are fetched live and may change frequently. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.