Mosquito season in Lake County, IN: when it starts and ends
Mosquito months in Lake County
In a normal year mosquito season in Lake County, IN starts around April 18 and ends around October 22, about 27 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Lake County, and when
- Start tipping out standing water weekly by April 4.
- Book any yard treatment for mid April, ahead of the July peak.
- Repellent can go away after October 22.
- 21 West Nile cases since 2016: you should wear EPA-registered repellent at dusk July to August, and check IN spray notices.
Lake County against the rest of IN
Lake County has the 82nd longest season of 92 IN counties, at 187 days against 231 in Floyd County and 177 in Steuben County. Its mean temperature is 49.9°F.
- Pulaski County: April 17 to October 22 (188 days, 0 WNV)
- Starke County: April 17 to October 21 (187 days, 0 WNV)
- Parke County: April 18 to October 22 (187 days, 0 WNV)
- Vermillion County: April 18 to October 22 (187 days, 0 WNV)
West Nile in Lake County
From 1999 to 2025, CDC ArboNET counted 118 human West Nile cases in Lake County (76 neuroinvasive) across 18 years. The worst was 2002 with 39; the latest was 2025.
See how the dates are worked out, and reading the West Nile counts.