Mosquito season in Armstrong County, PA: when it starts and ends
Mosquito months in Armstrong County
In a normal year mosquito season in Armstrong County, PA starts around April 23 and ends around October 20, about 26 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Armstrong 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 20.
- No West Nile cases since 2016, so bites in Armstrong County are a nuisance; check window screens.
Armstrong County against the rest of PA
Armstrong County has the 38th longest season of 67 PA counties, at 180 days against 222 in Philadelphia County and 154 in Clinton County. Its mean temperature is 49.8°F.
- Greene County: April 22 to October 22 (183 days, 0 WNV)
- Centre County: April 20 to October 18 (181 days, 5 WNV)
- Columbia County: April 22 to October 18 (179 days, 1 WNV)
- Luzerne County: April 22 to October 17 (178 days, 4 WNV)
West Nile in Armstrong County
From 1999 to 2025, CDC ArboNET counted 5 human West Nile cases in Armstrong County (1 neuroinvasive) across 2 years. The worst was 2003 with 3; the latest was 2004.
More: how the dates are worked out · when mosquitoes go away for the winter.