Mosquito season in Edgar County, IL: when it starts and ends

Mosquito months in Edgar County

In a normal year mosquito season in Edgar County, IL starts around April 11 and ends around October 25, about 28 weeks.

1. Jan
2. Feb
3. Mar
4. Apr
5. May
6. Jun
7. Jul
8. Aug
9. Sep
10. Oct
11. Nov
12. Dec

What to do in Edgar County, and when

• Start tipping out standing water weekly by March 28.
• Book any yard treatment for mid April, ahead of the July peak.
• Repellent can go away after October 25.
• 2 West Nile cases since 2016 (last 2023): you should use repellent at dusk June to August, more so if over 60.

Edgar County against the rest of IL

Edgar County has the 67th longest season of 102 IL counties, at 197 days against 232 in Pulaski County and 174 in Boone County. Its mean temperature is 51.6°F.

• Henderson County: April 10 to October 25 (198 days, 0 WNV)
• Schuyler County: April 10 to October 25 (198 days, 0 WNV)
• Livingston County: April 11 to October 25 (197 days, 0 WNV)
• Putnam County: April 11 to October 25 (197 days, 0 WNV)

West Nile in Edgar County

From 1999 to 2025, CDC ArboNET counted 4 human West Nile cases in Edgar County (4 neuroinvasive) across 3 years. The worst was 2002 with 2; the latest was 2023.

More: how the dates are worked out · when mosquitoes go away for the winter.