Newcastle, WY Weather Forecast
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Newcastle Weather Forecast
| TONIGHT | MONDAY | MONDAY NIGHT | TUESDAY | TUESDAY NIGHT | WEDNESDAY | WEDNESDAY NIGHT | THURSDAY | THURSDAY NIGHT | FRIDAY | FRIDAY NIGHT | SATURDAY |
| Mostly Clear | Sunny | Clear | Sunny | Clear | Sunny | Clear | Clearing | Chance of Rain | Chance of Rain | Chance of Rain | Clearing |
| Lo: 35°FLo: 2°C | Hi: 59°FHi: 15°C | Lo: 39°FLo: 4°C | Hi: 69°FHi: 21°C | Lo: 40°FLo: 4°C | Hi: 65°FHi: 18°C | Lo: 49°FLo: 9°C | Hi: 71°FHi: 22°C | Lo: 51°FLo: 11°C | Hi: 69°FHi: 21°C | Lo: 41°FLo: 5°C | Hi: 51°FHi: 11°C |
| POP: 20% | POP: 20% | POP: 50% | POP: 20% |
POP = Probability of Precipitation.
Weather Outlook Updated: 537 PM MDT Sun Oct 18 2026 

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Issued: 525 PM MDT Sun Oct 18 2026
Key Messages
- Warm and dry weather through much of this week.
Discussion
...(This Evening Through Sunday) Issued at 112 PM MDT Sun Oct 18 2026
Water vapor and upper air models show southwest flow over the region, as upper ridge sits to our east and an upper trough is located over the southwestern CONUS this afternoon. 18Z surface analysis shows a frontal boundary stretching from northeastern SD down into central WY, mostly through our forecast area now. Satellite shows clear skies over the forecast a...
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