Mosquito season in Knox County, ME: when it starts and ends
Mosquito months in Knox County
In a normal year mosquito season in Knox County, ME starts around May 8 and ends around October 15, about 23 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Knox County, and when
- Start tipping out standing water weekly by April 24.
- Book any yard treatment for early May, ahead of the July peak.
- Repellent can go away after October 15.
- No West Nile cases since 2016, so bites in Knox County are a nuisance; check window screens.
Knox County against the rest of ME
Knox County has the 5th longest season of 16 ME counties, at 160 days against 164 in Kennebec County and 133 in Franklin County. Its mean temperature is 46°F.
- Androscoggin County: May 2 to October 12 (163 days, 0 WNV)
- Cumberland County: May 3 to October 13 (163 days, 4 WNV)
- Washington County: May 6 to October 11 (158 days, 0 WNV)
- York County: May 3 to October 7 (157 days, 0 WNV)
West Nile in Knox County
CDC ArboNET lists no human West Nile cases for Knox County from 1999 to 2025, though virus turned up in birds, mosquitoes or horses in 2 of those years.
Background: when mosquitoes go away for the winter; how the dates are worked out.