Mosquito season in Delaware County, NY: when it starts and ends
Mosquito months in Delaware County
In a normal year mosquito season in Delaware County, NY starts around May 5 and ends around October 10, about 23 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Delaware County, and when
- Start tipping out standing water weekly by April 21.
- Book any yard treatment for early May, ahead of the July peak.
- Repellent can go away after October 10.
- No West Nile cases since 2016, so bites in Delaware County are a nuisance; check window screens.
Delaware County against the rest of NY
Delaware County has the 51st longest season of 62 NY counties, at 158 days against 218 in New York County and 125 in Franklin County. Its mean temperature is 45.3°F.
- Madison County: May 3 to October 9 (159 days, 0 WNV)
- Cortland County: May 4 to October 9 (158 days, 0 WNV)
- Wyoming County: May 5 to October 9 (157 days, 2 WNV)
- Lewis County: May 4 to October 7 (156 days, 0 WNV)
West Nile in Delaware County
CDC ArboNET lists no human West Nile cases for Delaware County from 1999 to 2025, though virus turned up in birds, mosquitoes or horses in 4 of those years.
Background: when mosquitoes go away for the winter; how the dates are worked out.