Mosquito season in Skagit County, WA: when it starts and ends
Mosquito months in Skagit County
In a normal year mosquito season in Skagit County, WA starts around April 26 and ends around October 14, about 24 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Skagit County, and when
- Start tipping out standing water weekly by April 12.
- Book any yard treatment for late April, ahead of the August peak.
- Repellent can go away after October 14.
- No West Nile cases since 2016, so bites in Skagit County are a nuisance; check window screens.
Skagit County against the rest of WA
Skagit County has the 21st longest season of 39 WA counties, at 171 days against 205 in Walla Walla County and 132 in Asotin County. Its mean temperature is 49.1°F.
- Pierce County: April 28 to October 17 (172 days, 2 WNV)
- Grays Harbor County: April 29 to October 18 (172 days, 0 WNV)
- Garfield County: April 25 to October 12 (169 days, 0 WNV)
- Whitman County: April 26 to October 11 (168 days, 1 WNV)
West Nile in Skagit County
From 1999 to 2025, CDC ArboNET counted 1 human West Nile case in Skagit County (0 neuroinvasive) across 1 year. The worst was 2013 with 1; the latest was 2013.
More: how the dates are worked out · when the season starts across the US.