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

Mosquito months in Davis County

In a normal year mosquito season in Davis County, IA starts around April 12 and ends around October 24, 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 Davis County, and when

• Start tipping out standing water weekly by March 29.
• Book any yard treatment for mid April, ahead of the July peak.
• Repellent can go away after October 24.
• No West Nile cases since 2016, so bites in Davis County are a nuisance; check window screens.

Davis County against the rest of IA

Davis County has the 3rd longest season of 99 IA counties, at 195 days against 198 in Des Moines County and 160 in Worth County. Its mean temperature is 51.2°F.

• Des Moines County: April 10 to October 25 (198 days, 3 WNV)
• Lee County: April 10 to October 25 (198 days, 1 WNV)
• Fremont County: April 13 to October 23 (193 days, 1 WNV)
• Wapello County: April 13 to October 22 (192 days, 0 WNV)

West Nile in Davis County

CDC ArboNET lists no human West Nile cases for Davis County from 1999 to 2025, though virus turned up in birds, mosquitoes or horses in 8 of those years.

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