Mosquito season in Mackinac County, MI: when it starts and ends

Mosquito months in Mackinac County

In a normal year mosquito season in Mackinac County, MI starts around May 12 and ends around October 3, about 21 weeks.

1. Jan
2. Feb
3. Mar
4. Apr
5. May
6. Jun
7. Jul
8. Aug
9. Sep
10. Oct
11. Nov
12. Dec

What to do in Mackinac County, and when

• Start tipping out standing water weekly by April 28.
• Book any yard treatment for mid May, ahead of the July peak.
• Repellent can go away after October 3.
• No West Nile cases since 2016, so bites in Mackinac County are a nuisance; check window screens.

Mackinac County against the rest of MI

Mackinac County has the 72nd longest season of 83 MI counties, at 144 days against 189 in Allegan County and 124 in Iron County. Its mean temperature is 41.8°F.

• Chippewa County: May 11 to October 3 (145 days, 0 WNV)
• Dickinson County: May 11 to October 3 (145 days, 0 WNV)
• Alcona County: May 17 to October 7 (143 days, 0 WNV)
• Marquette County: May 15 to October 4 (142 days, 1 WNV)

West Nile in Mackinac County

CDC ArboNET lists no human West Nile cases for Mackinac County from 1999 to 2025, though virus turned up in birds, mosquitoes or horses in 5 of those years.

Background: when the season starts across the US; how the dates are worked out.