Mosquito season in Racine County, WI: when it starts and ends
Mosquito months in Racine County
In a normal year mosquito season in Racine County, WI starts around April 30 and ends around October 20, about 25 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Racine County, and when
- Start tipping out standing water weekly by April 16.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 20.
- 4 West Nile cases since 2016 (last 2024): you should use repellent at dusk July to August, more so if over 60.
Racine County against the rest of WI
Racine County has the 13th longest season of 72 WI counties, at 173 days against 180 in La Crosse County and 139 in Rusk County. Its mean temperature is 48°F.
- Grant County: April 24 to October 14 (173 days, 0 WNV)
- Sauk County: April 24 to October 15 (173 days, 0 WNV)
- Columbia County: April 25 to October 13 (171 days, 0 WNV)
- Lafayette County: April 25 to October 13 (171 days, 1 WNV)
West Nile in Racine County
From 1999 to 2025, CDC ArboNET counted 12 human West Nile cases in Racine County (4 neuroinvasive) across 7 years. The worst was 2002 with 4; the latest was 2024.
More: how the dates are worked out · reading the West Nile counts.