The Green Bay year in pollen
Pollen seasons in Green Bay: tree pollen March to June, grass May to July, and ragweed from mid-August until the first frost, around October 9.
Tree pollen
Grass
Ragweed
When does ragweed season end in Green Bay?
Ragweed season in Green Bay typically ends with the first frost, around October 9. Some years it comes as early as October 3, some as late as October 16.
A light frost around October 9 knocks the season down; the hard freeze that finishes it usually follows by October 24. Based on 30 years of NOAA frost records (1991–2020).
The rest of the Green Bay pollen year
| Allergen | Typical season |
|---|---|
| Birch | April to May |
| Oak | April to June |
| Maple | March to May |
| Alder | March to April |
| Ash | April to May |
| Pine | May to June |
| Grass | May to July |
Season-by-season detail is on the Wisconsin page.
Nearby calendars
Frost dates for Green Bay come from the Green Bay weather station's 30-year records. Season windows reviewed August 2026.