Mosquito season in St. Tammany Parish, LA: when it starts and ends

Mosquito months in St. Tammany Parish

In a normal year mosquito season in St. Tammany Parish, LA starts around February 14 and ends around December 6, about 42 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 St. Tammany Parish, and when

• Start tipping out standing water weekly by January 31.
• Book any yard treatment for mid February, ahead of the July peak.
• Repellent can go away after December 6.
• 38 West Nile cases since 2016: you should wear EPA-registered repellent at dusk May to September, and check LA spray notices.

St. Tammany Parish against the rest of LA

St. Tammany Parish has the 38th longest season of 64 LA counties, at 295 days against 358 in Orleans Parish and 247 in Claiborne Parish. Its mean temperature is 67.5°F.

• Caddo Parish: February 11 to December 10 (302 days, 47 WNV)
• Madison Parish: February 13 to December 10 (300 days, 1 WNV)
• Rapides Parish: February 16 to December 7 (294 days, 29 WNV)
• East Carroll Parish: February 21 to December 6 (288 days, 0 WNV)

West Nile in St. Tammany Parish

From 1999 to 2025, CDC ArboNET counted 172 human West Nile cases in St. Tammany Parish (101 neuroinvasive) across 23 years. The worst was 2002 with 40; the latest was 2025.

See how the dates are worked out, and reading the West Nile counts.