Mosquito season in Berrien County, MI: when it starts and ends
Mosquito months in Berrien County
In a normal year mosquito season in Berrien County, MI starts around April 18 and ends around October 23, about 27 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Berrien County, and when
- Start tipping out standing water weekly by April 4.
- Book any yard treatment for mid April, ahead of the July peak.
- Repellent can go away after October 23.
- 6 West Nile cases since 2016 (last 2024): you should use repellent at dusk July to August, more so if over 60.
Berrien County against the rest of MI
Berrien County has the 2nd longest season of 83 MI counties, at 188 days against 189 in Allegan County and 124 in Iron County. Its mean temperature is 50.1°F.
- Allegan County: April 21 to October 27 (189 days, 4 WNV)
- Van Buren County: April 22 to October 26 (187 days, 1 WNV)
- Monroe County: April 21 to October 22 (184 days, 7 WNV)
West Nile in Berrien County
From 1999 to 2025, CDC ArboNET counted 9 human West Nile cases in Berrien County (7 neuroinvasive) across 6 years. The worst was 2018 with 3; the latest was 2024.
Background: reading the West Nile counts; how the dates are worked out.