Mosquito season in Jefferson Parish, LA: when it starts and ends

Mosquito months in Jefferson Parish

In a normal year mosquito season in Jefferson Parish, LA starts around January 23 and ends around January 7, about 50 weeks.

1. Jan
2. Feb
3. Mar
4. Apr
5. May
6. Jun
7. Jul
8. Aug
9. Sep
10. Oct
11. Nov
12. Dec

What to do in Jefferson Parish, and when

• Start tipping out standing water weekly by January 9.
• Book any yard treatment for late January, ahead of the August peak.
• Repellent can go away after January 7.
• 7 West Nile cases since 2016 (last 2023): you should use repellent at dusk May to October, more so if over 60.

Jefferson Parish against the rest of LA

Jefferson Parish has the 6th longest season of 64 LA counties, at 349 days against 358 in Orleans Parish and 247 in Claiborne Parish. Its mean temperature is 69.4°F.

• Iberia Parish: January 21 to January 6 (350 days, 5 WNV)
• St. Mary Parish: January 21 to January 6 (350 days, 0 WNV)
• Cameron Parish: January 22 to January 3 (346 days, 0 WNV)
• Terrebonne Parish: January 26 to January 2 (341 days, 4 WNV)

West Nile in Jefferson Parish

From 1999 to 2025, CDC ArboNET counted 96 human West Nile cases in Jefferson Parish (65 neuroinvasive) across 16 years. The worst was 2002 with 41; the latest was 2023.

Background: where mosquitoes never stop; how the dates are worked out.