The Los Angeles year in pollen
Pollen seasons in Los Angeles: tree pollen January to June, grass March to July, and ragweed from early August, fading out by late November.
Unlike most of California, Los Angeles rarely sees a real frost, so ragweed fades out rather than stopping cold.
Tree pollen
Grass
Ragweed
When does ragweed season end in Los Angeles?
Ragweed around Los Angeles winds down on its own through late November — most winters never bring a season-ending freeze.
The rest of the Los Angeles pollen year
| Allergen | Typical season |
|---|---|
| Oak | March to May |
| Cypress and juniper | January to March |
| Alder | January to March |
| Olive | April to June |
| Walnut | April to May |
| Grass | March to July |
Season-by-season detail is on the California page.
Nearby calendars
Frost dates for Los Angeles come from the Los Angeles Dwtn Usc Campus weather station's 30-year records. Season windows reviewed August 2026.