Mosquito season in Monroe County, MO: when it starts and ends
Mosquito months in Monroe County
In a normal year mosquito season in Monroe County, MO starts around April 11 and ends around October 28, about 29 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Monroe County, and when
- Start tipping out standing water weekly by March 28.
- Book any yard treatment for mid April, ahead of the July peak.
- Repellent can go away after October 28.
- No West Nile cases since 2016, so bites in Monroe County are a nuisance; check window screens.
Monroe County against the rest of MO
Monroe County has the 93rd longest season of 115 MO counties, at 200 days against 242 in Pemiscot County and 187 in Crawford County. Its mean temperature is 52.9°F.
- Buchanan County: April 9 to October 26 (200 days, 7 WNV)
- Grundy County: April 9 to October 26 (200 days, 1 WNV)
- Dallas County: April 9 to October 25 (199 days, 1 WNV)
- Knox County: April 9 to October 25 (199 days, 0 WNV)
West Nile in Monroe County
From 1999 to 2025, CDC ArboNET counted 1 human West Nile case in Monroe County (0 neuroinvasive) across 1 year. The worst was 2002 with 1; the latest was 2002.
Background: when mosquitoes go away for the winter; how the dates are worked out.