Mosquito season in Jefferson County, AL: when it starts and ends
Mosquito months in Jefferson County
In a normal year mosquito season in Jefferson County, AL starts around March 7 and ends around November 24, about 37 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 February 21.
- Book any yard treatment for early March, ahead of the July peak.
- Repellent can go away after November 24.
- 34 West Nile cases since 2016: you should wear EPA-registered repellent at dusk May to September, and check AL spray notices.
Jefferson County against the rest of AL
Jefferson County has the 28th longest season of 67 AL counties, at 262 days against 330 in Montgomery County and 218 in Marion County. Its mean temperature is 63.4°F.
- Sumter County: March 4 to November 21 (262 days, 3 WNV)
- Fayette County: March 5 to November 22 (262 days, 1 WNV)
- St. Clair County: March 8 to November 24 (261 days, 0 WNV)
- Covington County: March 7 to November 22 (260 days, 1 WNV)
West Nile in Jefferson County
From 1999 to 2025, CDC ArboNET counted 76 human West Nile cases in Jefferson County (60 neuroinvasive) across 18 years. The worst was 2002 with 12; the latest was 2025.
More: how the dates are worked out · reading the West Nile counts.