Mosquito season in Ingham County, MI: when it starts and ends
Mosquito months in Ingham County
In a normal year mosquito season in Ingham County, MI starts around April 22 and ends around October 18, about 26 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Ingham County, and when
- Start tipping out standing water weekly by April 8.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 18.
- 12 West Nile cases since 2016: you should wear EPA-registered repellent at dusk July to August, and check MI spray notices.
Ingham County against the rest of MI
Ingham County has the 11th longest season of 83 MI counties, at 179 days against 189 in Allegan County and 124 in Iron County. Its mean temperature is 48.9°F.
- Jackson County: April 21 to October 18 (180 days, 3 WNV)
- Clinton County: April 23 to October 20 (180 days, 4 WNV)
- St. Joseph County: April 22 to October 18 (179 days, 3 WNV)
- Cass County: April 24 to October 20 (179 days, 2 WNV)
West Nile in Ingham County
From 1999 to 2025, CDC ArboNET counted 33 human West Nile cases in Ingham County (28 neuroinvasive) across 12 years. The worst was 2002 with 8; the latest was 2025.
More: how the dates are worked out · reading the West Nile counts.