Mosquito season in Bergen County, NJ: when it starts and ends
Mosquito months in Bergen County
In a normal year mosquito season in Bergen County, NJ starts around April 9 and ends around November 2, about 30 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Bergen County, and when
- Start tipping out standing water weekly by March 26.
- Book any yard treatment for early April, ahead of the July peak.
- Repellent can go away after November 2.
- 31 West Nile cases since 2016: you should wear EPA-registered repellent at dusk June to August, and check NJ spray notices.
Bergen County against the rest of NJ
Bergen County has the 8th longest season of 21 NJ counties, at 208 days against 217 in Cape May County and 184 in Sussex County. Its mean temperature is 54.3°F.
- Gloucester County: April 7 to November 3 (211 days, 6 WNV)
- Union County: April 7 to November 3 (210 days, 10 WNV)
- Cumberland County: April 10 to November 2 (206 days, 5 WNV)
- Middlesex County: April 10 to November 1 (205 days, 20 WNV)
West Nile in Bergen County
From 1999 to 2025, CDC ArboNET counted 54 human West Nile cases in Bergen County (38 neuroinvasive) across 16 years. The worst was 2018 with 10; the latest was 2025.
Background: reading the West Nile counts; how the dates are worked out.