Mosquito season in Oregon County, MO: when it starts and ends
Mosquito months in Oregon County
In a normal year mosquito season in Oregon County, MO starts around April 5 and ends around October 30, about 30 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Oregon County, and when
- Start tipping out standing water weekly by March 22.
- Book any yard treatment for early April, ahead of the July peak.
- Repellent can go away after October 30.
- 1 West Nile case since 2016 (last 2025): you should use repellent at dusk June to August, more so if over 60.
Oregon County against the rest of MO
Oregon County has the 74th longest season of 115 MO counties, at 208 days against 242 in Pemiscot County and 187 in Crawford County. Its mean temperature is 55.7°F.
- Lafayette County: April 4 to October 29 (208 days, 0 WNV)
- Saline County: April 4 to October 29 (208 days, 1 WNV)
- Perry County: April 5 to October 30 (208 days, 0 WNV)
- Pettis County: April 5 to October 30 (208 days, 0 WNV)
West Nile in Oregon County
From 1999 to 2025, CDC ArboNET counted 1 human West Nile case in Oregon County (0 neuroinvasive) across 1 year. The worst was 2025 with 1; the latest was 2025.
Background: when mosquitoes go away for the winter; how the dates are worked out.