Mosquito season in Des Moines County, IA: when it starts and ends
Mosquito months in Des Moines County
In a normal year mosquito season in Des Moines 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 Des Moines 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.
- 3 West Nile cases since 2016 (last 2018): you should use repellent at dusk June to August, more so if over 60.
Des Moines County against the rest of IA
Des Moines County has the 1st longest season of 99 IA counties, at 198 days against 198 in Des Moines County and 160 in Worth County. Its mean temperature is 51.7°F.
- Lee County: April 10 to October 25 (198 days, 1 WNV)
- Davis County: April 12 to October 24 (195 days, 0 WNV)
West Nile in Des Moines County
From 1999 to 2025, CDC ArboNET counted 6 human West Nile cases in Des Moines County (3 neuroinvasive) across 5 years. The worst was 2018 with 2; the latest was 2018.
More: how the dates are worked out · when mosquitoes go away for the winter.