Mosquito season in Lafayette County, WI: when it starts and ends
Mosquito months in Lafayette County
In a normal year mosquito season in Lafayette County, WI starts around April 25 and ends around October 13, about 24 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Lafayette County, and when
- Start tipping out standing water weekly by April 11.
- 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 July, more so if over 60.
Lafayette County against the rest of WI
Lafayette County has the 15th longest season of 72 WI counties, at 171 days against 180 in La Crosse County and 139 in Rusk County. Its mean temperature is 46.3°F.
- Racine County: April 30 to October 20 (173 days, 4 WNV)
- Columbia County: April 25 to October 13 (171 days, 0 WNV)
- Fond du Lac County: April 27 to October 14 (171 days, 4 WNV)
- Winnebago County: April 27 to October 14 (170 days, 2 WNV)
West Nile in Lafayette County
From 1999 to 2025, CDC ArboNET counted 3 human West Nile cases in Lafayette County (2 neuroinvasive) across 2 years. The worst was 2013 with 2; the latest was 2017.
Background: when the season starts across the US; how the dates are worked out.