Mosquito season in Centre County, PA: when it starts and ends
Mosquito months in Centre County
In a normal year mosquito season in Centre County, PA starts around April 20 and ends around October 18, about 26 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Centre County, and when
- Start tipping out standing water weekly by April 6.
- Book any yard treatment for mid April, ahead of the July peak.
- Repellent can go away after October 18.
- 5 West Nile cases since 2016 (last 2023): you should use repellent at dusk July to July, more so if over 60.
Centre County against the rest of PA
Centre County has the 37th longest season of 67 PA counties, at 181 days against 222 in Philadelphia County and 154 in Clinton County. Its mean temperature is 49.1°F.
- Westmoreland County: April 20 to October 21 (184 days, 3 WNV)
- Greene County: April 22 to October 22 (183 days, 0 WNV)
- Armstrong County: April 23 to October 20 (180 days, 0 WNV)
- Columbia County: April 22 to October 18 (179 days, 1 WNV)
West Nile in Centre County
From 1999 to 2025, CDC ArboNET counted 7 human West Nile cases in Centre County (4 neuroinvasive) across 4 years. The worst was 2018 with 4; the latest was 2023.
Background: reading the West Nile counts; how the dates are worked out.