Mosquito season in Osage County, MO: when it starts and ends
Mosquito months in Osage County
In a normal year mosquito season in Osage County, MO starts around March 31 and ends around November 1, about 31 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Osage County, and when
- Start tipping out standing water weekly by March 17.
- Book any yard treatment for late March, ahead of the July peak.
- Repellent can go away after November 1.
- No West Nile cases since 2016, so bites in Osage County are a nuisance; check window screens.
Osage County against the rest of MO
Osage County has the 42nd longest season of 115 MO counties, at 215 days against 242 in Pemiscot County and 187 in Crawford County. Its mean temperature is 55.3°F.
- Dade County: March 31 to November 1 (215 days, 0 WNV)
- McDonald County: March 31 to November 1 (215 days, 0 WNV)
- Washington County: March 31 to November 1 (215 days, 0 WNV)
- Webster County: April 1 to November 2 (215 days, 1 WNV)
West Nile in Osage County
CDC ArboNET lists no human West Nile cases for Osage County from 1999 to 2025, though virus turned up in birds, mosquitoes or horses in 3 of those years.
More: how the dates are worked out · when the season starts across the US.