The Vermont year in pollen
Tree pollen in Vermont runs March to June, grass follows May to July, and ragweed starts in mid-August and holds on until the first frost — typically around October 3.
When does ragweed season end in Vermont?
Ragweed season in Vermont typically ends with the first frost, around October 3. The coldest corners of the state see frost by early October; the mildest hold out until mid-October.
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 Vermont
Tree pollen in Vermont starts in mid-March, and maple is usually first out. 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 Vermont 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 Vermont over several weeks, and ragweed season ends with it. Based on 30 years of NOAA frost records (1991–2020).
| City | Typical first frost |
|---|---|
| Burlington | October 15 |
| Rutland | October 3 |
Common questions
When does ragweed season end in Vermont?
Ragweed season in Vermont typically ends with the first frost, around October 3. The coldest corners of the state see frost by early October; the mildest hold out until mid-October.
When does allergy season end in Vermont?
The last big wave of the Vermont pollen year is ragweed, so the season ends with the first frost, around October 3. Tree pollen is done by June, grass mostly by July.
When does tree pollen start in Vermont?
Tree pollen in Vermont starts in mid-March, and maple is usually first out. 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.