Mosquito season in Allen County, IN: when it starts and ends
Mosquito months in Allen County
In a normal year mosquito season in Allen County, IN starts around April 16 and ends around October 23, about 27 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Allen County, and when
- Start tipping out standing water weekly by April 2.
- Book any yard treatment for mid April, ahead of the July peak.
- Repellent can go away after October 23.
- 11 West Nile cases since 2016: you should wear EPA-registered repellent at dusk June to August, and check IN spray notices.
Allen County against the rest of IN
Allen County has the 71st longest season of 92 IN counties, at 190 days against 231 in Floyd County and 177 in Steuben County. Its mean temperature is 50.5°F.
- Putnam County: April 15 to October 22 (190 days, 0 WNV)
- Adams County: April 16 to October 23 (190 days, 0 WNV)
- Grant County: April 16 to October 23 (190 days, 2 WNV)
- Jasper County: April 16 to October 22 (189 days, 2 WNV)
West Nile in Allen County
From 1999 to 2025, CDC ArboNET counted 122 human West Nile cases in Allen County (88 neuroinvasive) across 16 years. The worst was 2002 with 69; the latest was 2025.
Background: reading the West Nile counts; how the dates are worked out.