Mosquito season in Warren County, NJ: when it starts and ends
Mosquito months in Warren County
In a normal year mosquito season in Warren County, NJ starts around April 18 and ends around October 21, about 27 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Warren 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 October 21.
- 7 West Nile cases since 2016 (last 2024): you should use repellent at dusk July to August, more so if over 60.
Warren County against the rest of NJ
Warren County has the 20th longest season of 21 NJ counties, at 186 days against 217 in Cape May County and 184 in Sussex County. Its mean temperature is 50.3°F.
- Passaic County: April 17 to October 26 (192 days, 7 WNV)
- Morris County: April 18 to October 22 (188 days, 8 WNV)
- Sussex County: April 19 to October 20 (184 days, 2 WNV)
West Nile in Warren County
From 1999 to 2025, CDC ArboNET counted 7 human West Nile cases in Warren County (6 neuroinvasive) across 2 years. The worst was 2018 with 5; the latest was 2024.
Background: reading the West Nile counts; how the dates are worked out.