Mosquito season in Adams County, WI: when it starts and ends

Mosquito months in Adams County

In a normal year mosquito season in Adams County, WI starts around April 29 and ends around October 10, about 23 weeks.

What to do in Adams County, and when

Start tipping out standing water weekly by April 15.
Book any yard treatment for late April, ahead of the July peak.
Repellent can go away after October 10.
1 West Nile case since 2016 (last 2021): you should use repellent at dusk July to July, more so if over 60.

Adams County against the rest of WI

Adams County has the 27th longest season of 72 WI counties, at 164 days against 180 in La Crosse County and 139 in Rusk County. Its mean temperature is 45°F.

Calumet County: April 30 to October 12 (165 days, 3 WNV)
Washington County: May 1 to October 12 (165 days, 2 WNV)
Outagamie County: April 29 to October 11 (164 days, 5 WNV)
Brown County: April 30 to October 12 (164 days, 7 WNV)

West Nile in Adams County

From 1999 to 2025, CDC ArboNET counted 2 human West Nile cases in Adams County (1 neuroinvasive) across 2 years. The worst was 2021 with 1; the latest was 2021.

See how the dates are worked out, and when mosquitoes go away for the winter.