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

Mosquito months in Cumberland County

In a normal year mosquito season in Cumberland County, PA starts around April 13 and ends around October 26, about 28 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 Cumberland County, and when

• Start tipping out standing water weekly by March 30.
• Book any yard treatment for mid April, ahead of the July peak.
• Repellent can go away after October 26.
• 8 West Nile cases since 2016 (last 2025): you should use repellent at dusk July to August, more so if over 60.

Cumberland County against the rest of PA

Cumberland County has the 15th longest season of 67 PA counties, at 196 days against 222 in Philadelphia County and 154 in Clinton County. Its mean temperature is 52°F.

• Lebanon County: April 12 to October 26 (197 days, 14 WNV)
• Washington County: April 12 to October 25 (196 days, 3 WNV)
• Juniata County: April 13 to October 26 (196 days, 0 WNV)
• Northampton County: April 13 to October 26 (196 days, 4 WNV)

West Nile in Cumberland County

From 1999 to 2025, CDC ArboNET counted 16 human West Nile cases in Cumberland County (9 neuroinvasive) across 6 years. The worst was 2025 with 6; the latest was 2025.

More: how the dates are worked out · reading the West Nile counts.