Frost dates · Montana
When is the first frost in Missoula?
In a typical year, Missoula’s first frost comes around September 26 and its last around May 16.
One year in ten the first frost comes as early as September 12, and nine years in ten it has arrived by October 8. One year in ten the last frost is over as early as May 3, and nine years in ten it is over by June 1. Missoula averages about 173 nights a year at 32°F or colder, with about 130 frost-free days in between in a typical year. It’s frost season here, and the last frost usually comes around May 16. That makes it the 4th earliest first frost of the 117 cities we track where it freezes most years.
Last updated
A freeze is in the forecast for the next 48 hours.
Missoula’s first frost lands in late September, right when the valley had finally stopped being smug about summer.
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 12 | September 26 | October 8 |
| Last frost | May 3 | May 16 | June 1 |
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
- Flagstaff, Arizona: first frost around September 28
- Great Falls, Montana: first frost around September 24
Source: NOAA U.S. Climate Normals, 1991 to 2020, station USW00024153.