Mosquito season in Coos County, OR: when it starts and ends
Mosquito months in Coos County
In a normal year mosquito season in Coos County, OR starts around April 12 and ends around November 10, about 30 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Coos County, and when
- Start tipping out standing water weekly by March 29.
- Book any yard treatment for mid April, ahead of the August peak.
- Repellent can go away after November 10.
- No West Nile cases since 2016, so bites in Coos County are a nuisance; check window screens.
Coos County against the rest of OR
Coos County has the 3rd longest season of 36 OR counties, at 212 days against 225 in Curry County and 95 in Klamath County. Its mean temperature is 52.7°F.
- Curry County: March 27 to November 8 (225 days, 0 WNV)
- Multnomah County: March 30 to November 3 (218 days, 1 WNV)
- Josephine County: April 4 to November 1 (211 days, 0 WNV)
- Douglas County: April 7 to October 29 (204 days, 0 WNV)
West Nile in Coos County
From 1999 to 2025, CDC ArboNET counted 1 human West Nile case in Coos County (0 neuroinvasive) across 1 year. The worst was 2012 with 1; the latest was 2012.
See how the dates are worked out, and when the season starts across the US.