Sullivan, WI Weather & Growing Conditions

Local forecast, frost dates, hardiness zone and planting guidance for Sullivan, a village in Jefferson County, Wisconsin.

Tonight

61°F

Showers And Thunderstorms

Showers and thunderstorms. Some of the storms could produce heavy rain. Cloudy, with a low around 61. East wind 10 to 15 mph. Chance of precipitation is 100%. New rainfall amounts between 1 and 2 inches possible.

7-day forecast for Sullivan

When	Temp	Forecast	Wind	Precip
Tonight	61°F	Showers And Thunderstorms	10 to 15 mph E	96%
Saturday	70°F	Showers And Thunderstorms	5 to 15 mph SE	99%
Saturday Night	59°F	Showers And Thunderstorms	5 to 10 mph NE	75%
Sunday	65°F	Chance Rain Showers	10 to 15 mph NE	37%
Sunday Night	53°F	Mostly Cloudy	10 to 15 mph NE	8%
Monday	63°F	Slight Chance Rain Showers	10 to 15 mph NE	16%
Monday Night	48°F	Mostly Cloudy	5 to 10 mph NE	14%
Tuesday	61°F	Partly Sunny	10 to 15 mph NE	14%
Tuesday Night	47°F	Partly Cloudy	5 to 10 mph NE	8%
Wednesday	64°F	Partly Sunny	5 to 10 mph NE	8%
Wednesday Night	48°F	Partly Cloudy	0 to 5 mph NE	4%
Thursday	66°F	Partly Sunny	0 to 5 mph NE	3%
Thursday Night	49°F	Partly Cloudy	0 to 5 mph NE	4%
Friday	69°F	Mostly Sunny	0 to 5 mph N	4%

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

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

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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 Sep 19, 2026.