Janesville, WI Weather & Growing Conditions
Today
84°F
Partly Sunny
Partly sunny, with a high near 84. Southwest wind around 10 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 84°F | Partly Sunny | 10 mph SW | 12% |
| Tonight | 65°F | Chance Showers And Thunderstorms then Showers And Thunderstorms Likely | 5 to 10 mph W | 89% |
| Wednesday | 75°F | Patchy Fog | 5 mph W | 76% |
| Wednesday Night | 58°F | Chance Showers And Thunderstorms | 0 to 5 mph NW | 48% |
| Thursday | 78°F | Chance Rain Showers then Mostly Sunny | 0 to 5 mph NE | 27% |
| Thursday Night | 56°F | Mostly Clear | 0 mph | 9% |
| Friday | 80°F | Mostly Sunny | 0 to 5 mph S | 2% |
| Friday Night | 61°F | Mostly Clear | 0 to 5 mph S | 5% |
| Saturday | 82°F | Mostly Sunny | 5 to 10 mph SW | 12% |
| Saturday Night | 66°F | Slight Chance Showers And Thunderstorms | 5 to 10 mph SW | 27% |
| Sunday | 84°F | Chance Showers And Thunderstorms | 5 to 15 mph SW | 27% |
| Sunday Night | 66°F | Chance Showers And Thunderstorms | 5 to 10 mph SW | 46% |
| Monday | 82°F | Chance Rain Showers | 5 to 10 mph S | 44% |
| Monday Night | 65°F | Chance Showers And Thunderstorms | 5 to 10 mph NW | 44% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Janesville, WI
Last spring frost
Apr 26
First fall frost
Oct 15
Growing season
170 days
Hardiness zone
5b
Explore more for Janesville, WI: full frost dates · planting calendar · Wisconsin frost dates
Climate data from the nearest NOAA station, Afton - Janesville Wwtp, Wi (6 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.