Mosquito season in Cumberland County, IL: when it starts and ends
Mosquito months in Cumberland County
In a normal year mosquito season in Cumberland County, IL starts around April 3 and ends around October 31, about 30 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Cumberland County, and when
- Start tipping out standing water weekly by March 20.
- Book any yard treatment for early April, ahead of the July peak.
- Repellent can go away after October 31.
- No West Nile cases since 2016, so bites in Cumberland County are a nuisance; check window screens.
Cumberland County against the rest of IL
Cumberland County has the 30th longest season of 102 IL counties, at 211 days against 232 in Pulaski County and 174 in Boone County. Its mean temperature is 54.2°F.
- Pope County: April 2 to October 31 (212 days, 0 WNV)
- Coles County: April 3 to October 31 (211 days, 4 WNV)
- Effingham County: April 3 to October 31 (211 days, 1 WNV)
- Jasper County: April 3 to October 31 (211 days, 0 WNV)
West Nile in Cumberland County
From 1999 to 2025, CDC ArboNET counted 3 human West Nile cases in Cumberland County (1 neuroinvasive) across 1 year. The worst was 2002 with 3; the latest was 2002.
More: how the dates are worked out · when mosquitoes go away for the winter.