The Reno year in pollen
Pollen seasons in Reno: tree pollen March to June, grass May to July, and ragweed from early August until the first frost, around October 23.
Reno's pollen year runs on a different clock than most of Nevada — the seasons below follow Reno's own climate, not the statewide picture.
When does ragweed season end in Reno?
Ragweed season in Reno typically ends with the first frost, around October 23. Some years it comes as early as October 18, some as late as October 29.
A light frost around October 23 knocks the season down; the hard freeze that finishes it usually follows by November 2. Based on 30 years of NOAA frost records (1991–2020).
The rest of the Reno pollen year
| Allergen | Typical season |
|---|---|
| Juniper | March to May |
| Cottonwood and aspen | March to May |
| Maple (boxelder) | March to May |
| Birch and alder | April to May |
| Pine | May to June |
| Grass | May to July |
Season-by-season detail is on the Nevada page.
Nearby calendars
Frost dates for Reno come from the Reno Tahoe International Airport weather station's 30-year records. Season windows reviewed August 2026.