The Las Vegas year in pollen
Pollen seasons in Las Vegas: tree pollen February to June, grass April to October, and ragweed from early August until the first frost, around December 10.
First frost lands around December 10 in Las Vegas — about 48 days later than Nevada overall — which shifts when ragweed season ends here.
When does ragweed season end in Las Vegas?
Ragweed season in Las Vegas typically ends with the first frost, around December 10. Some years it comes as early as December 4, some as late as December 18.
A light frost around December 10 knocks the season down; the hard freeze that finishes it usually follows by December 25. Based on 30 years of NOAA frost records (1991–2020).
The rest of the Las Vegas pollen year
| Allergen | Typical season |
|---|---|
| Juniper | February to April |
| Mulberry | February to April |
| Ash | February to April |
| Olive | April to May |
| Mesquite | April to June |
| Grass | April to October |
Season-by-season detail is on the Nevada page.
Nearby calendars
Frost dates for Las Vegas come from the Las Vegas Air Terminal weather station's 30-year records. Season windows reviewed August 2026.