Mosquito season in Dallas County, IA: when it starts and ends
Mosquito months in Dallas County
In a normal year mosquito season in Dallas County, IA starts around April 16 and ends around October 19, about 27 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Dallas County, and when
- Start tipping out standing water weekly by April 2.
- Book any yard treatment for mid April, ahead of the July peak.
- Repellent can go away after October 19.
- No West Nile cases since 2016, so bites in Dallas County are a nuisance; check window screens.
Dallas County against the rest of IA
Dallas County has the 27th longest season of 99 IA counties, at 186 days against 198 in Des Moines County and 160 in Worth County. Its mean temperature is 49.4°F.
- Appanoose County: April 17 to October 21 (187 days, 1 WNV)
- Linn County: April 17 to October 21 (187 days, 4 WNV)
- Adair County: April 17 to October 20 (186 days, 0 WNV)
- Clinton County: April 17 to October 19 (186 days, 3 WNV)
West Nile in Dallas County
From 1999 to 2025, CDC ArboNET counted 6 human West Nile cases in Dallas County (5 neuroinvasive) across 4 years. The worst was 2013 with 2; the latest was 2015.
Background: when the season starts across the US; how the dates are worked out.