Mosquito season in Suffolk County, NY: when it starts and ends
Mosquito months in Suffolk County
In a normal year mosquito season in Suffolk County, NY starts around April 18 and ends around November 1, about 28 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Suffolk County, and when
- Start tipping out standing water weekly by April 4.
- Book any yard treatment for mid April, ahead of the July peak.
- Repellent can go away after November 1.
- 79 West Nile cases since 2016: you should wear EPA-registered repellent at dusk July to August, and check NY spray notices.
Suffolk County against the rest of NY
Suffolk County has the 7th longest season of 62 NY counties, at 197 days against 218 in New York County and 125 in Franklin County. Its mean temperature is 52.5°F.
- Richmond County: April 7 to November 6 (214 days, 31 WNV)
- Queens County: April 10 to November 7 (211 days, 82 WNV)
- Westchester County: April 19 to October 24 (188 days, 42 WNV)
- Rockland County: April 20 to October 23 (186 days, 6 WNV)
West Nile in Suffolk County
From 1999 to 2025, CDC ArboNET counted 171 human West Nile cases in Suffolk County (115 neuroinvasive) across 23 years. The worst was 2010 with 24; the latest was 2025.
See how the dates are worked out, and reading the West Nile counts.