Boulder, MT Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Boulder, a city in Jefferson County, Montana.
Today
75°F
Patchy Smoke
Patchy smoke. Sunny, with a high near 75. East wind 2 to 7 mph.
7-day forecast for Boulder
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 75°F | Patchy Smoke | 2 to 7 mph E | 0% |
| Tonight | 48°F | Patchy Smoke then Mostly Clear | 1 to 7 mph NW | 1% |
| Wednesday | 82°F | Sunny then Patchy Smoke | 2 to 8 mph W | 0% |
| Wednesday Night | 51°F | Patchy Smoke then Mostly Clear | 3 to 8 mph WNW | 0% |
| Thursday | 90°F | Sunny | 2 to 10 mph W | 0% |
| Thursday Night | 56°F | Mostly Clear | 3 to 10 mph WNW | 0% |
| Friday | 93°F | Sunny | 2 to 17 mph WSW | 0% |
| Friday Night | 57°F | Mostly Clear | 5 to 17 mph WNW | 0% |
| Saturday | 91°F | Sunny | 2 to 12 mph W | 0% |
| Saturday Night | 57°F | Mostly Clear | 3 to 14 mph NW | 1% |
| Sunday | 89°F | Sunny | 2 to 9 mph WNW | 1% |
| Sunday Night | 56°F | Mostly Clear | 3 to 10 mph NW | 1% |
| Monday | 87°F | Sunny | 2 to 8 mph NNE | 3% |
| Monday Night | 55°F | Mostly Clear | 2 to 9 mph NNW | 4% |
Forecast source: National Weather Service (api.weather.gov) for Boulder (46.236, -112.120). Updated through the day.
Growing snapshot for Boulder
Last spring frost
Jun 7
First fall frost
Sep 8
Growing season
90 days
Hardiness zone
5a
More local growing data for Boulder: nearby ZIP 59632 weather · frost dates · planting calendar · Montana frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Boulder, Mt (6.8 mi from Boulder). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.