Mosquito season in Sullivan County, NY: when it starts and ends
Mosquito months in Sullivan County
In a normal year mosquito season in Sullivan County, NY starts around May 2 and ends around October 10, about 23 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Sullivan County, and when
- Start tipping out standing water weekly by April 18.
- Book any yard treatment for early May, ahead of the July peak.
- Repellent can go away after October 10.
- 2 West Nile cases since 2016 (last 2024): you should use repellent at dusk July, more so if over 60.
Sullivan County against the rest of NY
Sullivan County has the 46th longest season of 62 NY counties, at 161 days against 218 in New York County and 125 in Franklin County. Its mean temperature is 45.5°F.
- Schuyler County: May 2 to October 11 (162 days, 0 WNV)
- Tioga County: May 2 to October 11 (162 days, 1 WNV)
- St. Lawrence County: May 2 to October 9 (160 days, 3 WNV)
- Cattaraugus County: May 3 to October 10 (160 days, 1 WNV)
West Nile in Sullivan County
From 1999 to 2025, CDC ArboNET counted 2 human West Nile cases in Sullivan County (1 neuroinvasive) across 2 years. The worst was 2024 with 1; the latest was 2024.
Background: when the season starts across the US; how the dates are worked out.