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City of Roundup, MTRoundup, MT Weather Forecast
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Roundup Weather Forecast
| TONIGHT | SUNDAY | SUNDAY NIGHT | LABOR DAY | MONDAY NIGHT | TUESDAY | TUESDAY NIGHT | WEDNESDAY | WEDNESDAY NIGHT | THURSDAY | THURSDAY NIGHT | FRIDAY |
 |  |  |  |  |  | | | | | |  |
| Partly Cloudy | Partly Sunny | Chance of T-Storm | Chance of T-Storm | Mostly Clear | Sunny | Mostly Clear | Mostly Sunny | Mostly Clear | Sunny | Mostly Clear | Rain Showers |
| Lo: 55°FLo: 13°C | Hi: 81°FHi: 27°C | Lo: 59°FLo: 15°C | Hi: 79°FHi: 26°C | Lo: 50°FLo: 10°C | Hi: 71°FHi: 22°C | Lo: 45°FLo: 7°C | Hi: 80°FHi: 27°C | Lo: 49°FLo: 9°C | Hi: 85°FHi: 29°C | Lo: 51°FLo: 11°C | Hi: 79°FHi: 26°C |
| POP: 70% | POP: 40% | POP: 20% |
POP = Probability of Precipitation.
Weather Outlook Updated: 350 PM MDT Sat Sep 05 2026 
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Meteorlogic Glosserator
Instant definitions for any meteorological term.
Instant definitions for any meteorological term.
Issued: 534 PM MDT Sat Sep 5 2026
Key Messages
- A weather system brings the chance of showers and thunderstorms to the area late Sunday into Monday. Thunderstorms will be capable of producing heavy rain and gusty winds. Cannot rule out hail with discrete thunderstorms on Sunday as well.
- Windy conditions are expected Monday into Tuesday (wind gusts of 25 to 50 mph, strongest in south-central MT Monday and eastern MT Tuesday). This will cause elevated fire weather conditions.
- Drier and warmer conditions are likely during the middle ...