Janesville, WI Weather & Growing Conditions
Today
71°F
Chance Showers And Thunderstorms then Showers And Thunderstorms
A chance of showers and thunderstorms before 11am, then showers and thunderstorms. Cloudy, with a high near 71. Southeast wind 5 to 10 mph. Chance of precipitation is 80%. New rainfall amounts between three quarters and one inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 71°F | Chance Showers And Thunderstorms then Showers And Thunderstorms | 5 to 10 mph SE | 79% |
| Tonight | 60°F | Showers And Thunderstorms | 5 to 10 mph E | 84% |
| Sunday | 64°F | Rain Showers | 10 to 15 mph NE | 76% |
| Sunday Night | 51°F | Mostly Cloudy | 10 to 15 mph NE | 13% |
| Monday | 62°F | Slight Chance Rain Showers | 15 mph NE | 21% |
| Monday Night | 47°F | Slight Chance Rain Showers then Mostly Cloudy | 10 to 15 mph NE | 16% |
| Tuesday | 60°F | Partly Sunny | 10 to 15 mph NE | 12% |
| Tuesday Night | 46°F | Partly Cloudy | 5 to 10 mph NE | 5% |
| Wednesday | 63°F | Mostly Sunny | 5 to 15 mph NE | 3% |
| Wednesday Night | 48°F | Partly Cloudy | 5 to 10 mph NE | 0% |
| Thursday | 65°F | Mostly Sunny | 5 to 10 mph NE | 4% |
| Thursday Night | 49°F | Partly Cloudy | 0 to 5 mph NE | 4% |
| Friday | 69°F | Partly Sunny | 0 to 10 mph NE | 3% |
| Friday Night | 49°F | Partly Cloudy | 0 to 5 mph NE | 3% |
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 Sep 19, 2026.