Mosquito season in Ferry County, WA: when it starts and ends

Mosquito months in Ferry County

In a normal year mosquito season in Ferry County, WA starts around May 12 and ends around September 24, about 19 weeks.

1. Jan
2. Feb
3. Mar
4. Apr
5. May
6. Jun
7. Jul
8. Aug
9. Sep
10. Oct
11. Nov
12. Dec

What to do in Ferry County, and when

• Start tipping out standing water weekly by April 28.
• Book any yard treatment for mid May, ahead of the July peak.
• Repellent can go away after September 24.
• No West Nile cases since 2016, so bites in Ferry County are a nuisance; check window screens.

Ferry County against the rest of WA

Ferry County has the 38th longest season of 39 WA counties, at 135 days against 205 in Walla Walla County and 132 in Asotin County. Its mean temperature is 44.3°F.

• Lincoln County: May 9 to October 1 (145 days, 0 WNV)
• Chelan County: May 11 to September 30 (142 days, 0 WNV)
• Asotin County: May 13 to September 22 (132 days, 0 WNV)

West Nile in Ferry County

CDC ArboNET lists no human West Nile cases for Ferry County from 1999 to 2025.

See how the dates are worked out, and when mosquitoes go away for the winter.