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

Mosquito months in Fulton County

In a normal year mosquito season in Fulton 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 Fulton 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.
• 1 West Nile case since 2016 (last 2018): you should use repellent at dusk June to August, more so if over 60.

Fulton County against the rest of IL

Fulton County has the 70th longest season of 102 IL counties, at 196 days against 232 in Pulaski County and 174 in Boone County. Its mean temperature is 51.4°F.

• Livingston County: April 11 to October 25 (197 days, 0 WNV)
• Putnam County: April 11 to October 25 (197 days, 0 WNV)
• Piatt County: April 11 to October 23 (195 days, 0 WNV)
• Kankakee County: April 14 to October 25 (194 days, 4 WNV)

West Nile in Fulton County

From 1999 to 2025, CDC ArboNET counted 10 human West Nile cases in Fulton County (6 neuroinvasive) across 3 years. The worst was 2002 with 8; the latest was 2018.

Background: when the season starts across the US; how the dates are worked out.