Hamilton, MT Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Hamilton, a city in Ravalli County, Montana.
Tonight
48°F
Showers And Thunderstorms
Showers and thunderstorms before 2am, then rain showers and patchy fog. Cloudy, with a low around 48. Southwest wind 1 to 5 mph. Chance of precipitation is 90%. New rainfall amounts between a half and three quarters of an inch possible.
7-day forecast for Hamilton
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 48°F | Showers And Thunderstorms | 1 to 5 mph SW | 91% |
| Saturday | 65°F | Rain Showers Likely | 0 to 3 mph NNW | 67% |
| Saturday Night | 45°F | Partly Cloudy | 3 mph SSW | 6% |
| Sunday | 74°F | Sunny | 5 mph W | 0% |
| Sunday Night | 46°F | Mostly Clear | 5 mph S | 0% |
| Monday | 77°F | Sunny | 5 mph SSW | 0% |
| Monday Night | 47°F | Mostly Clear | 5 mph WSW | 0% |
| Tuesday | 76°F | Sunny | 5 mph SSW | 0% |
| Tuesday Night | 47°F | Mostly Clear | 5 mph W | 4% |
| Wednesday | 76°F | Sunny | 6 mph SSW | 2% |
| Wednesday Night | 46°F | Mostly Clear | 5 mph SW | 1% |
| Thursday | 79°F | Sunny | 5 mph SSW | 1% |
| Thursday Night | 48°F | Partly Cloudy | 2 to 8 mph SW | 1% |
| Friday | 77°F | Mostly Sunny | 7 mph SSW | 2% |
Forecast source: National Weather Service (api.weather.gov) for Hamilton (46.252, -114.160). Updated through the day.
Growing snapshot for Hamilton
Last spring frost
May 21
First fall frost
Sep 22
Growing season
122 days
Hardiness zone
5b
More local growing data for Hamilton: nearby ZIP 59840 weather · frost dates · planting calendar · Montana frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Hamilton, Mt (6.3 mi from Hamilton). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.