Janesville, WI Weather & Growing Conditions
Overnight
56°F
Light Rain
Rain. Cloudy, with a low around 56. South wind around 15 mph, with gusts as high as 30 mph. Chance of precipitation is 90%. New rainfall amounts between a tenth and quarter of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 56°F | Light Rain | 15 mph S | 92% |
| Wednesday | 60°F | Chance Light Rain | 15 mph SW | 27% |
| Wednesday Night | 44°F | Cloudy | 15 mph SW | 14% |
| Thursday | 54°F | Chance Light Rain | 10 to 15 mph W | 52% |
| Thursday Night | 37°F | Chance Light Rain then Mostly Cloudy | 10 to 15 mph N | 32% |
| Friday | 47°F | Partly Sunny | 10 to 15 mph N | 4% |
| Friday Night | 31°F | Partly Cloudy | 0 to 10 mph N | 2% |
| Saturday | 51°F | Mostly Sunny | 0 to 5 mph W | 4% |
| Saturday Night | 32°F | Partly Cloudy | 0 to 5 mph SW | 5% |
| Sunday | 57°F | Mostly Sunny then Slight Chance Light Rain | 5 to 10 mph W | 17% |
| Sunday Night | 33°F | Mostly Clear | 5 mph W | 5% |
| Monday | 59°F | Sunny | 5 to 15 mph SW | 1% |
| Monday Night | 38°F | Mostly Clear | 5 to 10 mph W | 1% |
| Tuesday | 60°F | Sunny | 5 to 10 mph W | 1% |
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 Nov 4, 2026.