Mosquito season in Black Hawk County, IA: when it starts and ends
Mosquito months in Black Hawk County
In a normal year mosquito season in Black Hawk County, IA starts around April 18 and ends around October 18, about 26 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Black Hawk County, and when
- Start tipping out standing water weekly by April 4.
- Book any yard treatment for mid April, ahead of the July peak.
- Repellent can go away after October 18.
- No West Nile cases since 2016, so bites in Black Hawk County are a nuisance; check window screens.
Black Hawk County against the rest of IA
Black Hawk County has the 37th longest season of 99 IA counties, at 183 days against 198 in Des Moines County and 160 in Worth County. Its mean temperature is 48.6°F.
- Keokuk County: April 18 to October 19 (184 days, 1 WNV)
- Union County: April 18 to October 19 (184 days, 0 WNV)
- Jasper County: April 18 to October 18 (183 days, 1 WNV)
- Decatur County: April 19 to October 19 (183 days, 0 WNV)
West Nile in Black Hawk County
From 1999 to 2025, CDC ArboNET counted 6 human West Nile cases in Black Hawk County (1 neuroinvasive) across 5 years. The worst was 2005 with 2; the latest was 2007.
See how the dates are worked out, and when the season starts across the US.