Mosquito season in Franklin County, NY: when it starts and ends
Mosquito months in Franklin County
In a normal year mosquito season in Franklin County, NY starts around May 21 and ends around September 23, about 18 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Franklin County, and when
- Start tipping out standing water weekly by May 7.
- Book any yard treatment for late May, ahead of the July peak.
- Repellent can go away after September 23.
- 1 West Nile case since 2016 (last 2025): you should use repellent at dusk July, more so if over 60.
Franklin County against the rest of NY
Franklin County has the 62nd longest season of 62 NY counties, at 125 days against 218 in New York County and 125 in Franklin County. Its mean temperature is 40.1°F.
- Fulton County: May 10 to October 1 (145 days, 0 WNV)
- Essex County: May 13 to September 29 (139 days, 0 WNV)
West Nile in Franklin County
From 1999 to 2025, CDC ArboNET counted 1 human West Nile case in Franklin County (1 neuroinvasive) across 1 year. The worst was 2025 with 1; the latest was 2025.
More: how the dates are worked out · when mosquitoes go away for the winter.