Mosquito season in Calhoun County, MI: when it starts and ends
Mosquito months in Calhoun County
In a normal year mosquito season in Calhoun County, MI starts around April 21 and ends around October 19, about 26 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 7.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 19.
- 3 West Nile cases since 2016 (last 2024): you should use repellent at dusk July to August, more so if over 60.
Calhoun County against the rest of MI
Calhoun County has the 8th longest season of 83 MI counties, at 181 days against 189 in Allegan County and 124 in Iron County. Its mean temperature is 49°F.
- Wayne County: April 21 to October 21 (183 days, 110 WNV)
- Lenawee County: April 20 to October 19 (182 days, 3 WNV)
- Jackson County: April 21 to October 18 (180 days, 3 WNV)
- Clinton County: April 23 to October 20 (180 days, 4 WNV)
West Nile in Calhoun County
From 1999 to 2025, CDC ArboNET counted 3 human West Nile cases in Calhoun County (3 neuroinvasive) across 3 years. The worst was 2024 with 1; the latest was 2024.
See how the dates are worked out, and when mosquitoes go away for the winter.