Mosquito season in Seneca County, NY: when it starts and ends

Mosquito months in Seneca County

In a normal year mosquito season in Seneca County, NY starts around April 28 and ends around October 16, about 24 weeks.

1. Jan
2. Feb
3. Mar
4. Apr
5. May
6. Jun
7. Jul
8. Aug
9. Sep
10. Oct
11. Nov
12. Dec

What to do in Seneca County, and when

• Start tipping out standing water weekly by April 14.
• Book any yard treatment for late April, ahead of the July peak.
• Repellent can go away after October 16.
• No West Nile cases since 2016, so bites in Seneca County are a nuisance; check window screens.

Seneca County against the rest of NY

Seneca County has the 26th longest season of 62 NY counties, at 171 days against 218 in New York County and 125 in Franklin County. Its mean temperature is 47.6°F.

• Onondaga County: April 27 to October 17 (173 days, 10 WNV)
• Cayuga County: April 28 to October 16 (171 days, 0 WNV)
• Chemung County: April 27 to October 14 (170 days, 1 WNV)
• Schenectady County: April 26 to October 12 (169 days, 3 WNV)

West Nile in Seneca County

CDC ArboNET lists no human West Nile cases for Seneca County from 1999 to 2025, though virus turned up in birds, mosquitoes or horses in 5 of those years.

See how the dates are worked out, and when mosquitoes go away for the winter.