The Milwaukee year in pollen
Pollen seasons in Milwaukee: tree pollen March to June, grass May to July, and ragweed from mid-August until the first frost, around October 29.
First frost lands around October 29 in Milwaukee — about 19 days later than Wisconsin overall — which shifts when ragweed season ends here.
When does ragweed season end in Milwaukee?
Ragweed season in Milwaukee typically ends with the first frost, around October 29. Some years it comes as early as October 24, some as late as November 2.
A light frost around October 29 knocks the season down; the hard freeze that finishes it usually follows by November 8. Based on 30 years of NOAA frost records (1991–2020).
The rest of the Milwaukee 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 Milwaukee come from the Milwaukee Mitchell Airport weather station's 30-year records. Season windows reviewed August 2026.