Fort Smith, MT Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Fort Smith, a community in Big Horn County, Montana.
Tonight
32°F
Clear then Patchy Fog
Patchy fog between 2am and 5am. Clear, with a low around 32. West southwest wind 2 to 7 mph.
7-day forecast for Fort Smith
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 32°F | Clear then Patchy Fog | 2 to 7 mph WSW | 0% |
| Wednesday | 52°F | Sunny | 0 to 5 mph NNW | 0% |
| Wednesday Night | 33°F | Patchy Fog | 6 mph SW | 0% |
| Thursday | 58°F | Patchy Fog then Sunny | 1 to 7 mph WSW | 1% |
| Thursday Night | 34°F | Partly Cloudy then Patchy Fog | 1 to 6 mph WSW | 3% |
| Friday | 57°F | Patchy Fog then Sunny | 3 to 10 mph SW | 3% |
| Friday Night | 39°F | Partly Cloudy | 9 to 18 mph SW | 5% |
| Saturday | 61°F | Sunny | 6 to 14 mph SW | 1% |
| Saturday Night | 40°F | Mostly Clear | 6 to 20 mph SSW | 0% |
| Sunday | 68°F | Mostly Sunny | 13 to 23 mph SW | 0% |
| Sunday Night | 40°F | Partly Cloudy | 3 to 14 mph SW | 0% |
| Monday | 61°F | Mostly Sunny | 5 mph SE | 1% |
| Monday Night | 41°F | Mostly Cloudy | 6 mph SSW | 1% |
| Tuesday | 64°F | Mostly Sunny | 7 mph WSW | 2% |
Forecast source: National Weather Service (api.weather.gov) for Fort Smith (45.317, -107.935). Updated through the day.
Growing snapshot for Fort Smith
Last spring frost
May 7
First fall frost
Oct 5
Growing season
151 days
Hardiness zone
5a
More local growing data for Fort Smith: nearby ZIP 59035 weather · frost dates · planting calendar · Montana frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Yellowtail Dam, Mt (0.8 mi from Fort Smith). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.