The New Jersey year in pollen
Tree pollen in New Jersey runs March to June, grass follows May to July, and ragweed starts in mid-August and holds on until the first frost — typically around November 10.
When does ragweed season end in New Jersey?
Ragweed season in New Jersey typically ends with the first frost, around November 10. The coldest corners of the state see frost by early November; the mildest hold out until late November.
Ragweed keeps releasing pollen until a freeze kills the plants, which is why the season has no fixed end date — it ends when the cold arrives. More on how frost ends ragweed season.
Tree pollen in New Jersey
Tree pollen in New Jersey starts in mid-March, and maple is usually first out. Oak — the bigger problem for most people — follows April to June. Mild springs pull the start earlier.
| Tree | Typical season | Heaviest weeks |
|---|---|---|
| Maple | March to April | early April to mid-April |
| Birch | April to May | mid-April to early May |
| Oak | April to June | early May to late May |
| Ash | April to May | — |
| Pine | May to June | mid-May to early June |
Grass season
Grass pollen in New Jersey runs May to July, heaviest early June to late June. The culprits are cool-season lawn and meadow grasses — timothy, bluegrass, orchard grass — which flower in one early-summer wave. More on grass seasons.
First frost — and ragweed's end — city by city
The first frost sweeps across New Jersey over several weeks, and ragweed season ends with it. Based on 30 years of NOAA frost records (1991–2020).
| City | Typical first frost |
|---|---|
| Atlantic City | November 21 |
| Newark | November 10 |
| Trenton | November 1 |
Common questions
When does ragweed season end in New Jersey?
Ragweed season in New Jersey typically ends with the first frost, around November 10. The coldest corners of the state see frost by early November; the mildest hold out until late November.
When does allergy season end in New Jersey?
The last big wave of the New Jersey pollen year is ragweed, so the season ends with the first frost, around November 10. Tree pollen is done by June, grass mostly by July.
When does tree pollen start in New Jersey?
Tree pollen in New Jersey starts in mid-March, and maple is usually first out. Oak — the bigger problem for most people — follows April to June. Mild springs pull the start earlier.
Sources: NOAA U.S. Climate Normals (1991–2020 frost records) · Asthma and Allergy Foundation of America — Ragweed Pollen. Season windows reviewed August 2026.