Grantsburg, WI Weather & Growing Conditions
Today
76°F
Mostly Sunny
Mostly sunny, with a high near 76. Northwest wind 5 to 10 mph, with gusts as high as 20 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 76°F | Mostly Sunny | 5 to 10 mph NW | 1% |
| Tonight | 50°F | Mostly Clear | 0 to 5 mph NW | 0% |
| Wednesday | 79°F | Sunny | 0 to 10 mph SW | 0% |
| Wednesday Night | 55°F | Mostly Clear | 5 mph SW | 0% |
| Thursday | 84°F | Sunny | 5 to 10 mph SW | 3% |
| Thursday Night | 61°F | Mostly Clear | 5 to 10 mph SW | 4% |
| Friday | 86°F | Sunny | 5 to 10 mph SW | 12% |
| Friday Night | 59°F | Chance Showers And Thunderstorms | 0 to 10 mph SW | 28% |
| Saturday | 84°F | Mostly Sunny then Slight Chance Showers And Thunderstorms | 0 to 5 mph SW | 16% |
| Saturday Night | 60°F | Chance Showers And Thunderstorms | 0 to 5 mph N | 52% |
| Sunday | 83°F | Chance Showers And Thunderstorms | 0 to 5 mph W | 48% |
| Sunday Night | 59°F | Partly Cloudy then Slight Chance Showers And Thunderstorms | 0 to 5 mph N | 15% |
| Monday | 82°F | Slight Chance Showers And Thunderstorms | 0 to 5 mph NE | 19% |
| Monday Night | 59°F | Partly Cloudy then Slight Chance Showers And Thunderstorms | 0 to 5 mph N | 20% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Grantsburg, WI
Last spring frost
May 11
First fall frost
Oct 1
Growing season
141 days
Hardiness zone
4a
Explore more for Grantsburg, WI: full frost dates · planting calendar · Wisconsin frost dates
Climate data from the nearest NOAA station, Grantsburg, Wi (1.5 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.