Mosquito season in Monroe County, NY: when it starts and ends
Mosquito months in Monroe County
In a normal year mosquito season in Monroe County, NY starts around April 25 and ends around October 20, about 26 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Monroe County, and when
- Start tipping out standing water weekly by April 11.
- Book any yard treatment for late April, ahead of the July peak.
- Repellent can go away after October 20.
- 13 West Nile cases since 2016: you should wear EPA-registered repellent at dusk July to August, and check NY spray notices.
Monroe County against the rest of NY
Monroe County has the 16th longest season of 62 NY counties, at 179 days against 218 in New York County and 125 in Franklin County. Its mean temperature is 49°F.
- Orleans County: April 24 to October 21 (180 days, 1 WNV)
- Columbia County: April 22 to October 18 (179 days, 2 WNV)
- Dutchess County: April 22 to October 17 (177 days, 8 WNV)
- Yates County: April 26 to October 19 (176 days, 0 WNV)
West Nile in Monroe County
From 1999 to 2025, CDC ArboNET counted 23 human West Nile cases in Monroe County (17 neuroinvasive) across 12 years. The worst was 2018 with 6; the latest was 2025.
Background: reading the West Nile counts; how the dates are worked out.