Mosquito season in Allegan County, MI: when it starts and ends
Mosquito months in Allegan County
In a normal year mosquito season in Allegan County, MI starts around April 21 and ends around October 27, about 27 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Allegan 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 27.
- 4 West Nile cases since 2016 (last 2025): you should use repellent at dusk July to August, more so if over 60.
Allegan County against the rest of MI
Allegan County has the 1st longest season of 83 MI counties, at 189 days against 189 in Allegan County and 124 in Iron County. Its mean temperature is 50.7°F.
- Berrien County: April 18 to October 23 (188 days, 6 WNV)
- Van Buren County: April 22 to October 26 (187 days, 1 WNV)
West Nile in Allegan County
From 1999 to 2025, CDC ArboNET counted 8 human West Nile cases in Allegan County (5 neuroinvasive) across 5 years. The worst was 2018 with 3; the latest was 2025.
See how the dates are worked out, and reading the West Nile counts.