Roundup, MT Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Roundup, a city in Musselshell County, Montana.
This Afternoon
53°F
Sunny
Sunny. High near 53, with temperatures falling to around 48 in the afternoon. South southwest wind around 7 mph.
7-day forecast for Roundup
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 53°F | Sunny | 7 mph SSW | 0% |
| Tonight | 29°F | Patchy Fog | 5 mph SW | 0% |
| Wednesday | 54°F | Patchy Fog then Sunny | 5 mph W | 0% |
| Wednesday Night | 30°F | Patchy Fog | 1 to 8 mph SSW | 0% |
| Thursday | 59°F | Patchy Fog then Mostly Sunny | 2 to 12 mph SW | 2% |
| Thursday Night | 31°F | Partly Cloudy | 1 to 6 mph WSW | 4% |
| Friday | 57°F | Sunny | 6 to 13 mph WSW | 3% |
| Friday Night | 36°F | Partly Cloudy | 8 to 12 mph WSW | 3% |
| Saturday | 61°F | Sunny | 6 to 12 mph SW | 0% |
| Saturday Night | 36°F | Partly Cloudy | 5 to 13 mph SW | 0% |
| Sunday | 65°F | Mostly Sunny | 8 to 16 mph SW | 0% |
| Sunday Night | 37°F | Mostly Cloudy | 5 to 8 mph WSW | 0% |
| Monday | 58°F | Mostly Sunny | 5 mph SW | 1% |
| Monday Night | 35°F | Mostly Cloudy | 2 to 7 mph SSW | 1% |
Forecast source: National Weather Service (api.weather.gov) for Roundup (46.448, -108.540). Updated through the day.
Growing snapshot for Roundup
Last spring frost
May 20
First fall frost
Sep 21
Growing season
124 days
Hardiness zone
4b
More local growing data for Roundup: nearby ZIP 59072 weather · frost dates · planting calendar · Montana frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Roundup, Mt (6.2 mi from Roundup). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.