Mosquito season in Champaign County, IL: when it starts and ends
Mosquito months in Champaign County
In a normal year mosquito season in Champaign County, IL starts around April 9 and ends around October 26, about 29 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Champaign County, and when
- Start tipping out standing water weekly by March 26.
- Book any yard treatment for early April, ahead of the July peak.
- Repellent can go away after October 26.
- 5 West Nile cases since 2016 (last 2024): you should use repellent at dusk June to August, more so if over 60.
Champaign County against the rest of IL
Champaign County has the 62nd longest season of 102 IL counties, at 200 days against 232 in Pulaski County and 174 in Boone County. Its mean temperature is 52.2°F.
- Menard County: April 9 to October 26 (201 days, 0 WNV)
- Logan County: April 8 to October 25 (200 days, 0 WNV)
- Peoria County: April 9 to October 25 (199 days, 12 WNV)
- De Witt County: April 9 to October 24 (198 days, 0 WNV)
West Nile in Champaign County
From 1999 to 2025, CDC ArboNET counted 9 human West Nile cases in Champaign County (8 neuroinvasive) across 7 years. The worst was 2018 with 2; the latest was 2024.
See how the dates are worked out, and reading the West Nile counts.