The Trenton year in pollen
Pollen seasons in Trenton: tree pollen March to June, grass May to July, and ragweed from mid-August until the first frost, around November 1.
First frost lands around November 1 in Trenton — about 9 days earlier than New Jersey overall — which shifts when ragweed season ends here.
When does ragweed season end in Trenton?
Ragweed season in Trenton typically ends with the first frost, around November 1. Some years it comes as early as October 25, some as late as November 5.
A light frost around November 1 knocks the season down; the hard freeze that finishes it usually follows by November 12. Based on 30 years of NOAA frost records (1991–2020).
The rest of the Trenton 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 New Jersey page.
Nearby calendars
Frost dates for Trenton come from the Trenton Mercer Co Airport weather station's 30-year records. Season windows reviewed August 2026.