Mosquito season in Fayette County, IA: when it starts and ends

Mosquito months in Fayette County

In a normal year mosquito season in Fayette County, IA starts around April 27 and ends around October 11, about 24 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 Fayette County, and when

• Start tipping out standing water weekly by April 13.
• Book any yard treatment for late April, ahead of the July peak.
• Repellent can go away after October 11.
• 1 West Nile case since 2016 (last 2018): you should use repellent at dusk July to July, more so if over 60.

Fayette County against the rest of IA

Fayette County has the 94th longest season of 99 IA counties, at 167 days against 198 in Des Moines County and 160 in Worth County. Its mean temperature is 45°F.

• Allamakee County: April 27 to October 12 (168 days, 1 WNV)
• Clayton County: April 27 to October 11 (167 days, 0 WNV)
• Chickasaw County: April 27 to October 10 (166 days, 2 WNV)
• Emmet County: April 27 to October 10 (166 days, 2 WNV)

West Nile in Fayette County

From 1999 to 2025, CDC ArboNET counted 3 human West Nile cases in Fayette County (1 neuroinvasive) across 3 years. The worst was 2018 with 1; the latest was 2018.

Background: when mosquitoes go away for the winter; how the dates are worked out.