Mosquito season in Greene County, PA: when it starts and ends

Mosquito months in Greene County

In a normal year mosquito season in Greene County, PA starts around April 22 and ends around October 22, about 26 weeks.

What to do in Greene County, and when

Start tipping out standing water weekly by April 8.
Book any yard treatment for late April, ahead of the July peak.
Repellent can go away after October 22.
No West Nile cases since 2016, so bites in Greene County are a nuisance; check window screens.

Greene County against the rest of PA

Greene County has the 36th longest season of 67 PA counties, at 183 days against 222 in Philadelphia County and 154 in Clinton County. Its mean temperature is 51.1°F.

Lycoming County: April 19 to October 20 (184 days, 1 WNV)
Westmoreland County: April 20 to October 21 (184 days, 3 WNV)
Centre County: April 20 to October 18 (181 days, 5 WNV)
Armstrong County: April 23 to October 20 (180 days, 0 WNV)

West Nile in Greene County

CDC ArboNET lists no human West Nile cases for Greene County from 1999 to 2025, though virus turned up in birds, mosquitoes or horses in 17 of those years.

See how the dates are worked out, and when the season starts across the US.