Mosquito season in Buffalo County, WI: when it starts and ends
Mosquito months in Buffalo County
In a normal year mosquito season in Buffalo County, WI starts around April 23 and ends around October 13, about 25 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Buffalo County, and when
- Start tipping out standing water weekly by April 9.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 13.
- 1 West Nile case since 2016 (last 2017): you should use repellent at dusk July to August, more so if over 60.
Buffalo County against the rest of WI
Buffalo County has the 10th longest season of 72 WI counties, at 173 days against 180 in La Crosse County and 139 in Rusk County. Its mean temperature is 46.2°F.
- Dane County: April 24 to October 15 (174 days, 36 WNV)
- Jefferson County: April 25 to October 16 (174 days, 7 WNV)
- Grant County: April 24 to October 14 (173 days, 0 WNV)
- Sauk County: April 24 to October 15 (173 days, 0 WNV)
West Nile in Buffalo County
From 1999 to 2025, CDC ArboNET counted 2 human West Nile cases in Buffalo County (2 neuroinvasive) across 2 years. The worst was 2017 with 1; the latest was 2017.
More: how the dates are worked out · when the season starts across the US.