Mosquito season in Adams County, WA: when it starts and ends
Mosquito months in Adams County
In a normal year mosquito season in Adams County, WA starts around April 23 and ends around October 16, about 25 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Adams County, and when
- Start tipping out standing water weekly by April 9.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 16.
- No West Nile cases since 2016, so bites in Adams County are a nuisance; check window screens.
Adams County against the rest of WA
Adams County has the 17th longest season of 39 WA counties, at 176 days against 205 in Walla Walla County and 132 in Asotin County. Its mean temperature is 50.7°F.
- Pacific County: April 24 to October 20 (179 days, 0 WNV)
- Thurston County: April 23 to October 18 (178 days, 1 WNV)
- Whatcom County: April 25 to October 14 (172 days, 1 WNV)
- Pierce County: April 28 to October 17 (172 days, 2 WNV)
West Nile in Adams County
CDC ArboNET lists no human West Nile cases for Adams 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 mosquitoes go away for the winter.