Mosquito season in Essex County, NJ: when it starts and ends
Mosquito months in Essex County
In a normal year mosquito season in Essex County, NJ starts around April 11 and ends around October 28, about 28 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Essex County, and when
- Start tipping out standing water weekly by March 28.
- Book any yard treatment for mid April, ahead of the July peak.
- Repellent can go away after October 28.
- 10 West Nile cases since 2016: you should wear EPA-registered repellent at dusk July to August, and check NJ spray notices.
Essex County against the rest of NJ
Essex County has the 13th longest season of 21 NJ counties, at 199 days against 217 in Cape May County and 184 in Sussex County. Its mean temperature is 52.7°F.
- Monmouth County: April 11 to November 2 (205 days, 25 WNV)
- Mercer County: April 10 to October 30 (204 days, 9 WNV)
- Ocean County: April 14 to October 29 (198 days, 9 WNV)
- Hunterdon County: April 13 to October 26 (195 days, 6 WNV)
West Nile in Essex County
From 1999 to 2025, CDC ArboNET counted 27 human West Nile cases in Essex County (17 neuroinvasive) across 14 years. The worst was 2021 with 4; the latest was 2025.
See how the dates are worked out, and reading the West Nile counts.