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

Mosquito months in St. Helena Parish

In a normal year mosquito season in St. Helena Parish, LA starts around February 20 and ends around January 3, about 45 weeks.

What to do in St. Helena Parish, and when

Start tipping out standing water weekly by February 6.
Book any yard treatment for mid February, ahead of the August peak.
Repellent can go away after January 3.
No West Nile cases since 2016, so bites in St. Helena Parish are a nuisance; check window screens.

St. Helena Parish against the rest of LA

St. Helena Parish has the 27th longest season of 64 LA counties, at 317 days against 358 in Orleans Parish and 247 in Claiborne Parish. Its mean temperature is 66.1°F.

St. Bernard Parish: February 2 to December 25 (326 days, 0 WNV)
Allen Parish: February 12 to January 4 (326 days, 4 WNV)
Lafayette Parish: February 5 to December 14 (312 days, 14 WNV)
East Baton Rouge Parish: February 6 to December 11 (308 days, 65 WNV)

West Nile in St. Helena Parish

From 1999 to 2025, CDC ArboNET counted 7 human West Nile cases in St. Helena Parish (6 neuroinvasive) across 4 years. The worst was 2012 with 2; the latest was 2012.

See how the dates are worked out, and when the season starts across the US.