Mosquito season in Scott County, IL: when it starts and ends
Mosquito months in Scott County
In a normal year mosquito season in Scott County, IL starts around April 7 and ends around October 27, about 29 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Scott County, and when
- Start tipping out standing water weekly by March 24.
- Book any yard treatment for early April, ahead of the July peak.
- Repellent can go away after October 27.
- 1 West Nile case since 2016 (last 2019): you should use repellent at dusk June to August, more so if over 60.
Scott County against the rest of IL
Scott County has the 50th longest season of 102 IL counties, at 203 days against 232 in Pulaski County and 174 in Boone County. Its mean temperature is 52.9°F.
- Greene County: April 7 to October 28 (204 days, 0 WNV)
- Sangamon County: April 7 to October 28 (204 days, 8 WNV)
- Vermilion County: April 8 to October 28 (203 days, 1 WNV)
- Brown County: April 8 to October 27 (202 days, 0 WNV)
West Nile in Scott County
From 1999 to 2025, CDC ArboNET counted 1 human West Nile case in Scott County (0 neuroinvasive) across 1 year. The worst was 2019 with 1; the latest was 2019.
See how the dates are worked out, and when mosquitoes go away for the winter.