The Columbia year in pollen
Pollen seasons in Columbia: tree pollen February to May, grass May to July, and ragweed from early August until the first frost, around October 29.
Tree pollen
Grass
Ragweed
When does ragweed season end in Columbia?
Ragweed season in Columbia typically ends with the first frost, around October 29. Some years it comes as early as October 23, some as late as November 2.
A light frost around October 29 knocks the season down; the hard freeze that finishes it usually follows by November 6. Based on 30 years of NOAA frost records (1991–2020).
The rest of the Columbia pollen year
| Allergen | Typical season |
|---|---|
| Oak | April to May |
| Maple | March to April |
| Elm | February to April |
| Birch | April to May |
| Ash | April to May |
| Hickory and walnut | April to May |
| Grass | May to July |
Season-by-season detail is on the Missouri page.
Nearby calendars
Frost dates for Columbia come from the Columbia Regional Airport weather station's 30-year records. Season windows reviewed August 2026.