Mosquito season in Fond du Lac County, WI: when it starts and ends
Mosquito months in Fond du Lac County
In a normal year mosquito season in Fond du Lac County, WI starts around April 27 and ends around October 14, about 24 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Fond du Lac County, and when
- Start tipping out standing water weekly by April 13.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 14.
- 4 West Nile cases since 2016 (last 2024): you should use repellent at dusk July to July, more so if over 60.
Fond du Lac County against the rest of WI
Fond du Lac County has the 16th longest season of 72 WI counties, at 171 days against 180 in La Crosse County and 139 in Rusk County. Its mean temperature is 46.5°F.
- Columbia County: April 25 to October 13 (171 days, 0 WNV)
- Lafayette County: April 25 to October 13 (171 days, 1 WNV)
- Winnebago County: April 27 to October 14 (170 days, 2 WNV)
- Waukesha County: April 28 to October 15 (170 days, 15 WNV)
West Nile in Fond du Lac County
From 1999 to 2025, CDC ArboNET counted 7 human West Nile cases in Fond du Lac County (6 neuroinvasive) across 7 years. The worst was 2024 with 1; the latest was 2024.
Background: reading the West Nile counts; how the dates are worked out.