The Louisiana year in pollen

When does ragweed season end in Louisiana?

Ragweed season in Louisiana typically ends with the first frost, around November 26. The coldest corners of the state see frost by late November; the mildest hold out until early January.

Ragweed keeps releasing pollen until a freeze kills the plants, which is why the season has no fixed end date — it ends when the cold arrives. More on how frost ends ragweed season.

Tree pollen in Louisiana

Tree pollen in Louisiana starts in early January, and eastern red cedar is usually first out. Oak — the bigger problem for most people — follows February to May. Mild springs pull the start earlier.

Grass season

Grass pollen in Louisiana runs April to September, heaviest early May to late August. Warm-season grasses like Bermuda do the damage here, and they keep flowering through the heat, which is why the season runs so long. More on grass seasons.

First frost — and ragweed's end — city by city

The first frost sweeps across Louisiana over several weeks, and ragweed season ends with it. Based on 30 years of NOAA frost records (1991–2020).

Common questions

When does ragweed season end in Louisiana?

Ragweed season in Louisiana typically ends with the first frost, around November 26. The coldest corners of the state see frost by late November; the mildest hold out until early January.

When does allergy season end in Louisiana?

The last big wave of the Louisiana pollen year is ragweed, so the season ends with the first frost, around November 26. Tree pollen is done by May, grass mostly by September.

When does tree pollen start in Louisiana?

Tree pollen in Louisiana starts in early January, and eastern red cedar is usually first out. Oak — the bigger problem for most people — follows February to May. Mild springs pull the start earlier.