Mosquito season in Sauk County, WI: when it starts and ends
Mosquito months in Sauk County
In a normal year mosquito season in Sauk County, WI starts around April 24 and ends around October 15, about 25 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Sauk County, and when
- Start tipping out standing water weekly by April 10.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 15.
- No West Nile cases since 2016, so bites in Sauk County are a nuisance; check window screens.
Sauk County against the rest of WI
Sauk County has the 12th longest season of 72 WI counties, at 173 days against 180 in La Crosse County and 139 in Rusk County. Its mean temperature is 46.5°F.
- Buffalo County: April 23 to October 13 (173 days, 1 WNV)
- Grant County: April 24 to October 14 (173 days, 0 WNV)
- Racine County: April 30 to October 20 (173 days, 4 WNV)
- Columbia County: April 25 to October 13 (171 days, 0 WNV)
West Nile in Sauk County
From 1999 to 2025, CDC ArboNET counted 1 human West Nile case in Sauk County (1 neuroinvasive) across 1 year. The worst was 2002 with 1; the latest was 2002.
See how the dates are worked out, and when mosquitoes go away for the winter.