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

Mosquito months in Bradford County

In a normal year mosquito season in Bradford County, PA starts around April 24 and ends around October 17, about 25 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 Bradford County, and when

• Start tipping out standing water weekly by April 10.
• Book any yard treatment for late April, ahead of the July peak.
• Repellent can go away after October 17.
• No West Nile cases since 2016, so bites in Bradford County are a nuisance; check window screens.

Bradford County against the rest of PA

Bradford County has the 43rd longest season of 67 PA counties, at 176 days against 222 in Philadelphia County and 154 in Clinton County. Its mean temperature is 48.6°F.

• Venango County: April 23 to October 18 (178 days, 1 WNV)
• Crawford County: April 23 to October 18 (177 days, 0 WNV)
• Clearfield County: April 23 to October 15 (175 days, 0 WNV)
• Indiana County: April 27 to October 19 (175 days, 1 WNV)

West Nile in Bradford County

CDC ArboNET lists no human West Nile cases for Bradford County from 1999 to 2025, though virus turned up in birds, mosquitoes or horses in 8 of those years.

Background: when the season starts across the US; how the dates are worked out.