Frost dates · Arizona
When is the first frost in Flagstaff?
Flagstaff right now
39°FMist
- Today44°F / 34°FRain
- Tomorrow55°F / 33°FClear skies
- Monday48°F / 33°FClouds
Consider a nap instead.
Live from OpenWeatherMap. Alerts from the National Weather Service.
In a typical year, Flagstaff’s first frost comes around September 28 and its last around June 4.
One year in ten the first frost comes as early as September 16, and nine years in ten it has arrived by October 9. One year in ten the last frost is over as early as May 21, and nine years in ten it is over by June 19. Flagstaff averages about 202 nights a year at 32°F or colder, with about 115 frost-free days in between in a typical year. It’s frost season here, and the last frost usually comes around June 4. That makes it the 6th earliest first frost of the 117 cities we track where it freezes most years.
Last updated
No freeze in the forecast for the next 48 hours.
Flagstaff can freeze into June, which is a bold move for a city that is technically in Arizona.
Live 48-hour check from OpenWeatherMap, refreshed about every half hour. Alerts from the National Weather Service.
Frost dates, early, typical and late years
| Early year (1 in 10) | Typical | Late year (1 in 10) | |
|---|---|---|---|
| First frost | September 16 | September 28 | October 9 |
| Last frost | May 21 | June 4 | June 19 |
A frost date here is a night when the official thermometer reads 32°F or colder. Frost on the ground can show up on clear, calm nights a few degrees milder.
Cities with about the same first frost
- Bismarck, North Dakota: first frost around September 27
- Fargo, North Dakota: first frost around September 30
- Helena, Montana: first frost around September 30
Source: NOAA U.S. Climate Normals, 1991 to 2020, station USW00003103.