Sullivan, WI Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Sullivan, a village in Jefferson County, Wisconsin.
Overnight
61°F
Mostly Clear
Mostly clear, with a low around 61. South wind around 5 mph.
7-day forecast for Sullivan
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 61°F | Mostly Clear | 5 mph S | 0% |
| Tuesday | 83°F | Mostly Sunny | 5 to 10 mph SW | 13% |
| Tuesday Night | 64°F | Chance Showers And Thunderstorms then Showers And Thunderstorms | 5 to 10 mph W | 91% |
| Wednesday | 75°F | Patchy Fog then Chance Showers And Thunderstorms | 5 mph W | 69% |
| Wednesday Night | 59°F | Chance Showers And Thunderstorms | 0 to 5 mph N | 39% |
| Thursday | 78°F | Slight Chance Rain Showers then Mostly Sunny | 0 to 5 mph NE | 21% |
| Thursday Night | 57°F | Mostly Clear | 0 to 5 mph E | 8% |
| Friday | 81°F | Sunny | 0 to 5 mph SW | 2% |
| Friday Night | 62°F | Mostly Clear | 0 to 5 mph SW | 5% |
| Saturday | 83°F | Mostly Sunny then Slight Chance Showers And Thunderstorms | 5 to 10 mph SW | 15% |
| Saturday Night | 67°F | Slight Chance Showers And Thunderstorms | 5 mph SW | 30% |
| Sunday | 84°F | Chance Showers And Thunderstorms | 5 to 10 mph SW | 30% |
| Sunday Night | 66°F | Chance Showers And Thunderstorms | 5 to 10 mph SW | 50% |
| Monday | 82°F | Chance Rain Showers | 5 mph S | 44% |
Forecast source: National Weather Service (api.weather.gov) for Sullivan (43.012, -88.595). Updated through the day.
Growing snapshot for Sullivan
Last spring frost
May 3
First fall frost
Oct 9
Growing season
157 days
Hardiness zone
5b
More local growing data for Sullivan: nearby ZIP 53178 weather · frost dates · planting calendar · Wisconsin frost dates
Nearby towns & communities
Fort Atkinson
Hebron
Helenville
Ixonia
Jefferson
Johnson Creek
Lake Mills
Palmyra
Rome
Waterloo
Watertown
Climate data from the nearest NOAA station, Sullivan 3Se, Wi (4.9 mi from Sullivan). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.