Mosquito season in Iosco County, MI: when it starts and ends
Mosquito months in Iosco County
In a normal year mosquito season in Iosco County, MI starts around May 6 and ends around October 10, about 22 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Iosco County, and when
- Start tipping out standing water weekly by April 22.
- Book any yard treatment for early May, ahead of the July peak.
- Repellent can go away after October 10.
- No West Nile cases since 2016, so bites in Iosco County are a nuisance; check window screens.
Iosco County against the rest of MI
Iosco County has the 49th longest season of 83 MI counties, at 157 days against 189 in Allegan County and 124 in Iron County. Its mean temperature is 45°F.
- Leelanau County: May 6 to October 13 (161 days, 1 WNV)
- Oscoda County: May 5 to October 9 (157 days, 1 WNV)
- Montcalm County: May 4 to October 7 (156 days, 3 WNV)
- Osceola County: May 5 to October 7 (156 days, 0 WNV)
West Nile in Iosco County
CDC ArboNET lists no human West Nile cases for Iosco County from 1999 to 2025, though virus turned up in birds, mosquitoes or horses in 8 of those years.
Background: when the season starts across the US; how the dates are worked out.