Mosquito season in Union County, NJ: when it starts and ends
Mosquito months in Union County
In a normal year mosquito season in Union County, NJ starts around April 7 and ends around November 3, about 30 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Union County, and when
- Start tipping out standing water weekly by March 24.
- Book any yard treatment for early April, ahead of the July peak.
- Repellent can go away after November 3.
- 10 West Nile cases since 2016: you should wear EPA-registered repellent at dusk June to August, and check NJ spray notices.
Union County against the rest of NJ
Union County has the 7th longest season of 21 NJ counties, at 210 days against 217 in Cape May County and 184 in Sussex County. Its mean temperature is 54.7°F.
- Camden County: April 6 to November 3 (211 days, 22 WNV)
- Gloucester County: April 7 to November 3 (211 days, 6 WNV)
- Bergen County: April 9 to November 2 (208 days, 31 WNV)
- Cumberland County: April 10 to November 2 (206 days, 5 WNV)
West Nile in Union County
From 1999 to 2025, CDC ArboNET counted 27 human West Nile cases in Union County (22 neuroinvasive) across 15 years. The worst was 2003 with 5; the latest was 2025.
Background: reading the West Nile counts; how the dates are worked out.