Mosquito season in Beaver County, PA: when it starts and ends
Mosquito months in Beaver County
In a normal year mosquito season in Beaver County, PA starts around April 17 and ends around October 23, about 27 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Beaver County, and when
- Start tipping out standing water weekly by April 3.
- Book any yard treatment for mid April, ahead of the July peak.
- Repellent can go away after October 23.
- 3 West Nile cases since 2016 (last 2021): you should use repellent at dusk July to August, more so if over 60.
Beaver County against the rest of PA
Beaver County has the 24th longest season of 67 PA counties, at 189 days against 222 in Philadelphia County and 154 in Clinton County. Its mean temperature is 50.7°F.
- Union County: April 15 to October 23 (191 days, 1 WNV)
- Mifflin County: April 16 to October 22 (190 days, 0 WNV)
- Blair County: April 17 to October 21 (188 days, 1 WNV)
- Dauphin County: April 18 to October 23 (188 days, 8 WNV)
West Nile in Beaver County
From 1999 to 2025, CDC ArboNET counted 5 human West Nile cases in Beaver County (4 neuroinvasive) across 4 years. The worst was 2018 with 2; the latest was 2021.
Background: when mosquitoes go away for the winter; how the dates are worked out.