Mosquito season in Hardin County, IL: when it starts and ends
Mosquito months in Hardin County
In a normal year mosquito season in Hardin County, IL starts around April 6 and ends around October 29, about 29 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Hardin County, and when
- Start tipping out standing water weekly by March 23.
- Book any yard treatment for early April, ahead of the July peak.
- Repellent can go away after October 29.
- No West Nile cases since 2016, so bites in Hardin County are a nuisance; check window screens.
Hardin County against the rest of IL
Hardin County has the 44th longest season of 102 IL counties, at 206 days against 232 in Pulaski County and 174 in Boone County. Its mean temperature is 55.5°F.
- Jersey County: April 5 to October 28 (206 days, 1 WNV)
- Calhoun County: April 6 to October 29 (206 days, 0 WNV)
- Macon County: April 6 to October 28 (205 days, 4 WNV)
- Moultrie County: April 6 to October 28 (205 days, 0 WNV)
West Nile in Hardin County
From 1999 to 2025, CDC ArboNET counted 1 human West Nile case in Hardin County (1 neuroinvasive) across 1 year. The worst was 2007 with 1; the latest was 2007.
Background: when the season starts across the US; how the dates are worked out.