Mosquito season in Lee County, IA: when it starts and ends
Mosquito months in Lee County
In a normal year mosquito season in Lee County, IA starts around April 10 and ends around October 25, about 28 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Lee County, and when
- Start tipping out standing water weekly by March 27.
- Book any yard treatment for early April, ahead of the July peak.
- Repellent can go away after October 25.
- 1 West Nile case since 2016 (last 2023): you should use repellent at dusk June to August, more so if over 60.
Lee County against the rest of IA
Lee County has the 2nd longest season of 99 IA counties, at 198 days against 198 in Des Moines County and 160 in Worth County. Its mean temperature is 51.8°F.
- Des Moines County: April 10 to October 25 (198 days, 3 WNV)
- Davis County: April 12 to October 24 (195 days, 0 WNV)
- Fremont County: April 13 to October 23 (193 days, 1 WNV)
West Nile in Lee County
From 1999 to 2025, CDC ArboNET counted 6 human West Nile cases in Lee County (4 neuroinvasive) across 5 years. The worst was 2002 with 2; the latest was 2023.
Background: when mosquitoes go away for the winter; how the dates are worked out.