Mosquito season in Calhoun County, IA: when it starts and ends
Mosquito months in Calhoun County
In a normal year mosquito season in Calhoun County, IA starts around April 22 and ends around October 16, about 25 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Calhoun County, and when
- Start tipping out standing water weekly by April 8.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 16.
- 2 West Nile cases since 2016 (last 2018): you should use repellent at dusk July to August, more so if over 60.
Calhoun County against the rest of IA
Calhoun County has the 57th longest season of 99 IA counties, at 177 days against 198 in Des Moines County and 160 in Worth County. Its mean temperature is 47.2°F.
- Dubuque County: April 21 to October 15 (177 days, 2 WNV)
- Ida County: April 21 to October 15 (177 days, 3 WNV)
- Winneshiek County: April 22 to October 16 (177 days, 0 WNV)
- Wright County: April 22 to October 16 (177 days, 1 WNV)
West Nile in Calhoun County
From 1999 to 2025, CDC ArboNET counted 6 human West Nile cases in Calhoun County (3 neuroinvasive) across 3 years. The worst was 2018 with 2; the latest was 2018.
Background: when mosquitoes go away for the winter; how the dates are worked out.