The Worcester year in pollen
Pollen seasons in Worcester: tree pollen March to June, grass May to July, and ragweed from mid-August until the first frost, around October 21.
Tree pollen
Grass
Ragweed
When does ragweed season end in Worcester?
Ragweed season in Worcester typically ends with the first frost, around October 21. Some years it comes as early as October 14, some as late as October 27.
A light frost around October 21 knocks the season down; the hard freeze that finishes it usually follows by November 1. Based on 30 years of NOAA frost records (1991–2020).
The rest of the Worcester pollen year
| Allergen | Typical season |
|---|---|
| Maple | March to April |
| Birch | April to May |
| Oak | April to June |
| Ash | April to May |
| Pine | May to June |
| Grass | May to July |
Season-by-season detail is on the Massachusetts page.
Nearby calendars
Frost dates for Worcester come from the Worcester Regional Airport weather station's 30-year records. Season windows reviewed August 2026.