Mosquito season in Jefferson County, WV: when it starts and ends
Mosquito months in Jefferson County
In a normal year mosquito season in Jefferson County, WV starts around April 7 and ends around October 29, about 29 weeks.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
What to do in Jefferson 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 October 29.
- 1 West Nile case since 2016 (last 2025): you should use repellent at dusk June to August, more so if over 60.
Jefferson County against the rest of WV
Jefferson County has the 13th longest season of 55 WV counties, at 206 days against 224 in Cabell County and 162 in Randolph County. Its mean temperature is 53.7°F.
- Berkeley County: April 6 to October 30 (207 days, 3 WNV)
- Clay County: April 6 to October 29 (206 days, 0 WNV)
- Braxton County: April 8 to October 31 (206 days, 0 WNV)
- Lincoln County: April 9 to October 30 (204 days, 0 WNV)
West Nile in Jefferson County
From 1999 to 2025, CDC ArboNET counted 1 human West Nile case in Jefferson County (1 neuroinvasive) across 1 year. The worst was 2025 with 1; the latest was 2025.
See how the dates are worked out, and when the season starts across the US.