NWS Forecast for Janesville WI

National Weather Service Forecast for: Janesville WI
Issued by: National Weather Service Milwaukee, WI

Updated: 7:37 am CST Dec 22, 2025

Today Cloudy then Slight Chance Rain	Tonight Mostly Cloudy	Tuesday Partly Sunny	Tuesday Night Mostly Cloudy	Wednesday Mostly Cloudy then Slight Chance Rain	Wednesday Night Slight Chance Rain then Cloudy	Christmas Day Cloudy then Slight Chance Rain	Thursday Night Chance Rain	Friday Mostly Sunny
Hi 38 °F	Lo 32 °F	Hi 42 °F	Lo 26 °F	Hi 42 °F	Lo 37 °F	Hi 42 °F	Lo 40 °F	Hi 48 °F

Hazardous Weather Outlook

Today	A slight chance of rain between 3pm and 4pm. Cloudy, with a high near 38. South wind 5 to 10 mph. Chance of precipitation is 20%.
Tonight	Mostly cloudy, with a low around 32. South wind around 5 mph becoming west after midnight.
Tuesday	Partly sunny, with a high near 42. Northwest wind around 5 mph.
Tuesday Night	Mostly cloudy, with a low around 26. Calm wind becoming east around 5 mph after midnight.
Wednesday	A 20 percent chance of rain after noon. Cloudy, with a high near 42. Southeast wind 5 to 10 mph.
Wednesday Night	A 20 percent chance of rain before midnight. Cloudy, with a low around 37. Southeast wind around 5 mph becoming calm.
Christmas Day	A 20 percent chance of rain after noon. Cloudy, with a high near 42. Calm wind becoming southeast around 5 mph in the morning.
Thursday Night	A 40 percent chance of rain, mainly before midnight. Mostly cloudy, with a low around 40. Southeast wind 5 to 10 mph becoming west after midnight.
Friday	Mostly sunny, with a high near 48.
Friday Night	Mostly cloudy, with a low around 32.
Saturday	Mostly cloudy, with a high near 45.
Saturday Night	A 20 percent chance of rain. Mostly cloudy, with a low around 21.
Sunday	Partly sunny, with a high near 30.

Forecast from NOAA-NWS for Janesville WI.