Mosquito season in Delaware County, IA: when it starts and ends
Mosquito months in Delaware County
In a normal year mosquito season in Delaware County, IA starts around April 24 and ends around October 13, about 25 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Delaware County, and when
- Start tipping out standing water weekly by April 10.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 13.
- No West Nile cases since 2016, so bites in Delaware County are a nuisance; check window screens.
Delaware County against the rest of IA
Delaware County has the 82nd longest season of 99 IA counties, at 172 days against 198 in Des Moines County and 160 in Worth County. Its mean temperature is 46.4°F.
- Cherokee County: April 24 to October 14 (173 days, 3 WNV)
- Lucas County: April 26 to October 16 (173 days, 1 WNV)
- Dickinson County: April 24 to October 13 (172 days, 1 WNV)
- Hamilton County: April 24 to October 12 (171 days, 0 WNV)
West Nile in Delaware County
From 1999 to 2025, CDC ArboNET counted 1 human West Nile case in Delaware County (0 neuroinvasive) across 1 year. The worst was 2005 with 1; the latest was 2005.
See how the dates are worked out, and when the season starts across the US.