The Fargo year in pollen
Pollen seasons in Fargo: tree pollen February to May, grass May to August, and ragweed from early August until the first frost, around September 30.
Tree pollen
Grass
Ragweed
When does ragweed season end in Fargo?
Ragweed season in Fargo typically ends with the first frost, around September 30. Some years it comes as early as September 25, some as late as October 5.
A light frost around September 30 knocks the season down; the hard freeze that finishes it usually follows by October 10. Based on 30 years of NOAA frost records (1991–2020).
The rest of the Fargo pollen year
| Allergen | Typical season |
|---|---|
| Eastern red cedar | February to April |
| Elm | February to April |
| Maple | March to April |
| Oak | April to May |
| Cottonwood | April to May |
| Grass | May to August |
Season-by-season detail is on the North Dakota page.
Nearby calendars
Frost dates for Fargo come from the Fargo Hector International Airport weather station's 30-year records. Season windows reviewed August 2026.