Mosquito season in Columbia County, PA: when it starts and ends
Mosquito months in Columbia County
In a normal year mosquito season in Columbia County, PA starts around April 22 and ends around October 18, about 26 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Columbia County, and when
- Start tipping out standing water weekly by April 8.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 18.
- 1 West Nile case since 2016 (last 2018): you should use repellent at dusk July to July, more so if over 60.
Columbia County against the rest of PA
Columbia County has the 39th longest season of 67 PA counties, at 179 days against 222 in Philadelphia County and 154 in Clinton County. Its mean temperature is 49.3°F.
- Centre County: April 20 to October 18 (181 days, 5 WNV)
- Armstrong County: April 23 to October 20 (180 days, 0 WNV)
- Luzerne County: April 22 to October 17 (178 days, 4 WNV)
- Venango County: April 23 to October 18 (178 days, 1 WNV)
West Nile in Columbia County
From 1999 to 2025, CDC ArboNET counted 1 human West Nile case in Columbia County (1 neuroinvasive) across 1 year. The worst was 2018 with 1; the latest was 2018.
More: how the dates are worked out · when the season starts across the US.