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

Mosquito months in Lycoming County

In a normal year mosquito season in Lycoming County, PA starts around April 19 and ends around October 20, about 26 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 Lycoming County, and when

• Start tipping out standing water weekly by April 5.
• Book any yard treatment for mid April, ahead of the July peak.
• Repellent can go away after October 20.
• 1 West Nile case since 2016 (last 2018): you should use repellent at dusk July to August, more so if over 60.

Lycoming County against the rest of PA

Lycoming County has the 34th longest season of 67 PA counties, at 184 days against 222 in Philadelphia County and 154 in Clinton County. Its mean temperature is 49.8°F.

• Schuylkill County: April 17 to October 21 (187 days, 4 WNV)
• Lackawanna County: April 18 to October 21 (186 days, 4 WNV)
• Westmoreland County: April 20 to October 21 (184 days, 3 WNV)
• Greene County: April 22 to October 22 (183 days, 0 WNV)

West Nile in Lycoming County

From 1999 to 2025, CDC ArboNET counted 2 human West Nile cases in Lycoming County (2 neuroinvasive) across 2 years. The worst was 2018 with 1; the latest was 2018.

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