The San Diego year in pollen
Pollen seasons in San Diego: tree pollen January to June, grass March to July, and ragweed from early August, fading out by late November.
Unlike most of California, San Diego rarely sees a real frost, so ragweed fades out rather than stopping cold.
Tree pollen
Grass
Ragweed
When does ragweed season end in San Diego?
Ragweed around San Diego winds down on its own through late November — most winters never bring a season-ending freeze.
The rest of the San Diego 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 San Diego come from the San Diego Lindbergh Field weather station's 30-year records. Season windows reviewed August 2026.