Climate change in Jefferson County, Wisconsin
Since 1979, Jefferson County, Wisconsin has warmed 2.4°F, with about the same number of days above 90°F, about the same number of nights above 70°F and 11% more precipitation a year. Its climate in 1996–2025 is most like Kane County, IL's was in 1951–1980.
- Average temperature: +2.4°F
- Summer highs (Jun–Aug): +0.5°F
- Winter lows (Dec–Feb): +4.7°F
- Precipitation: +11%
- Wettest day of the year: +44%
- Longest dry spell: −1 days
- Days above 90°F: −0 days
- Nights above 70°F: −0 days
- Freezing nights: −13 days
- Frost-free season: +12 days
- Muggy days: +2 days
- Summer heat index (Jun–Aug): +1.0°F
- Extreme fire-weather days: +11 days
- Snowfall: +10%
- Snowy days (1 inch or more): +0 days
Changes follow the trend line through every year from 1979 to 2025. Data: NOAA nClimGrid-Daily; humidity from gridMET, adjusted to airport observations.