Mosquito season in Hamilton County, NY: when it starts and ends
Mosquito months in Hamilton County
In a normal year mosquito season in Hamilton County, NY starts around May 9 and ends around October 3, about 21 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Hamilton County, and when
- Start tipping out standing water weekly by April 25.
- Book any yard treatment for early May, ahead of the July peak.
- Repellent can go away after October 3.
- No West Nile cases since 2016, so bites in Hamilton County are a nuisance; check window screens.
Hamilton County against the rest of NY
Hamilton County has the 59th longest season of 62 NY counties, at 147 days against 218 in New York County and 125 in Franklin County. Its mean temperature is 41.8°F.
- Greene County: May 7 to October 6 (151 days, 3 WNV)
- Herkimer County: May 8 to October 4 (149 days, 0 WNV)
- 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 Hamilton County
CDC ArboNET lists no human West Nile cases for Hamilton County from 1999 to 2025, though virus turned up in birds, mosquitoes or horses in 2 of those years.
Background: when the season starts across the US; how the dates are worked out.