Mosquito season in Gratiot County, MI: when it starts and ends
Mosquito months in Gratiot County
In a normal year mosquito season in Gratiot County, MI starts around April 27 and ends around October 14, about 24 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Gratiot County, and when
- Start tipping out standing water weekly by April 13.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 14.
- 1 West Nile case since 2016 (last 2020): you should use repellent at dusk July to July, more so if over 60.
Gratiot County against the rest of MI
Gratiot County has the 32nd longest season of 83 MI counties, at 170 days against 189 in Allegan County and 124 in Iron County. Its mean temperature is 47.1°F.
- Midland County: April 27 to October 15 (171 days, 0 WNV)
- Bay County: April 28 to October 16 (171 days, 4 WNV)
- Ionia County: April 27 to October 13 (170 days, 2 WNV)
- Manistee County: April 30 to October 17 (170 days, 0 WNV)
West Nile in Gratiot County
From 1999 to 2025, CDC ArboNET counted 1 human West Nile case in Gratiot County (1 neuroinvasive) across 1 year. The worst was 2020 with 1; the latest was 2020.
See how the dates are worked out, and when mosquitoes go away for the winter.