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

Mosquito months in St. Mary Parish

In a normal year mosquito season in St. Mary Parish, LA starts around January 21 and ends around January 6, about 50 weeks.

What to do in St. Mary Parish, and when

Start tipping out standing water weekly by January 7.
Book any yard treatment for late January, ahead of the August peak.
Repellent can go away after January 6.
No West Nile cases since 2016, so bites in St. Mary Parish are a nuisance; check window screens.

St. Mary Parish against the rest of LA

St. Mary Parish has the 5th longest season of 64 LA counties, at 350 days against 358 in Orleans Parish and 247 in Claiborne Parish. Its mean temperature is 69.8°F.

St. Charles Parish: January 20 to January 7 (352 days, 2 WNV)
Iberia Parish: January 21 to January 6 (350 days, 5 WNV)
Jefferson Parish: January 23 to January 7 (349 days, 7 WNV)
Cameron Parish: January 22 to January 3 (346 days, 0 WNV)

West Nile in St. Mary Parish

From 1999 to 2025, CDC ArboNET counted 2 human West Nile cases in St. Mary Parish (1 neuroinvasive) across 2 years. The worst was 2003 with 1; the latest was 2003.

More: how the dates are worked out · where mosquitoes never stop.