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

Mosquito months in Union Parish

In a normal year mosquito season in Union Parish, LA starts around March 2 and ends around November 29, about 39 weeks.

What to do in Union Parish, and when

Start tipping out standing water weekly by February 16.
Book any yard treatment for early March, ahead of the July peak.
Repellent can go away after November 29.
No West Nile cases since 2016, so bites in Union Parish are a nuisance; check window screens.

Union Parish against the rest of LA

Union Parish has the 54th longest season of 64 LA counties, at 272 days against 358 in Orleans Parish and 247 in Claiborne Parish. Its mean temperature is 64.8°F.

East Feliciana Parish: February 27 to December 1 (277 days, 5 WNV)
Bossier Parish: February 28 to November 29 (274 days, 19 WNV)
Webster Parish: March 1 to November 27 (271 days, 9 WNV)
LaSalle Parish: March 1 to November 25 (269 days, 1 WNV)

West Nile in Union Parish

From 1999 to 2025, CDC ArboNET counted 6 human West Nile cases in Union Parish (4 neuroinvasive) across 6 years. The worst was 2012 with 1; the latest was 2012.

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