Mosquito season in Somerset County, PA: when it starts and ends
Mosquito months in Somerset County
In a normal year mosquito season in Somerset County, PA starts around April 30 and ends around October 12, about 24 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Somerset County, and when
- Start tipping out standing water weekly by April 16.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 12.
- 2 West Nile cases since 2016 (last 2025): you should use repellent at dusk July, more so if over 60.
Somerset County against the rest of PA
Somerset County has the 53rd longest season of 67 PA counties, at 165 days against 222 in Philadelphia County and 154 in Clinton County. Its mean temperature is 46.6°F.
- Clarion County: April 29 to October 14 (168 days, 0 WNV)
- Pike County: April 29 to October 14 (168 days, 0 WNV)
- Tioga County: April 30 to October 12 (165 days, 2 WNV)
- Wyoming County: May 1 to October 13 (165 days, 0 WNV)
West Nile in Somerset County
From 1999 to 2025, CDC ArboNET counted 2 human West Nile cases in Somerset County (1 neuroinvasive) across 2 years. The worst was 2025 with 1; the latest was 2025.
See how the dates are worked out, and when the season starts across the US.