National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Watching Hurricane Erin; Heavy Rainfall Threat for Upper Midwest; Heatrisk for Mississippi Valley

Hurricane Erin continues to track westward with its outer bands bringing heavy rainfall and gusty winds for Puerto Rico and US Virgin Islands. Life-threatening surf and rip currents are occurring and will spread across the Atlantic coasts this week. Meanwhile, heavy rainfall and possible flooding are in the forecast for upper Midwest through Monday. Heatrisk continues for the Mississippi Valley. Read More >

Current conditions at

ROCKY BOY (RCBM8)

Lat: 48.25529°NLon: 109.78592°WElev: 3789.0ft.

NA

58°F

14°C

Humidity 84%
Wind Speed SSW 0 MPH
Barometer NA
Dewpoint 53°F (12°C)
Visibility NA
Last update 17 Aug 09:18 PM MDT
Extended Forecast for

Big Sandy MT

  • Tonight

    Tonight: Mostly cloudy, then gradually becoming mostly clear, with a low around 58. South wind around 6 mph.

    Low: 58 °F

    Decreasing
    Clouds

  • Monday

    Monday: A 20 percent chance of showers and thunderstorms after 5pm. Sunny, with a high near 90. South southwest wind 3 to 6 mph.

    High: 90 °F

    Sunny then
    Slight Chance
    T-storms

  • Monday Night

    Monday Night: Mostly clear, with a low around 62. Light and variable wind becoming south around 5 mph.

    Low: 62 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny and hot, with a high near 97. Light and variable wind.

    High: 97 °F

    Hot

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 62. Northeast wind 3 to 5 mph.

    Low: 62 °F

    Partly Cloudy

  • Wednesday

    Wednesday: Sunny, with a high near 94. Northwest wind 3 to 7 mph.

    High: 94 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 58. Northwest wind 6 to 8 mph.

    Low: 58 °F

    Partly Cloudy

  • Thursday

    Thursday: Sunny, with a high near 82. North northwest wind around 7 mph.

    High: 82 °F

    Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 54.

    Low: 54 °F

    Mostly Clear

Detailed Forecast

Tonight
Mostly cloudy, then gradually becoming mostly clear, with a low around 58. South wind around 6 mph.
Monday
A 20 percent chance of showers and thunderstorms after 5pm. Sunny, with a high near 90. South southwest wind 3 to 6 mph.
Monday Night
Mostly clear, with a low around 62. Light and variable wind becoming south around 5 mph.
Tuesday
Sunny and hot, with a high near 97. Light and variable wind.
Tuesday Night
Partly cloudy, with a low around 62. Northeast wind 3 to 5 mph.
Wednesday
Sunny, with a high near 94. Northwest wind 3 to 7 mph.
Wednesday Night
Partly cloudy, with a low around 58. Northwest wind 6 to 8 mph.
Thursday
Sunny, with a high near 82. North northwest wind around 7 mph.
Thursday Night
Mostly clear, with a low around 54.
Friday
Sunny, with a high near 79.
Friday Night
Mostly clear, with a low around 53.
Saturday
Sunny, with a high near 81.
Saturday Night
Mostly clear, with a low around 55.
Sunday
Sunny, with a high near 83.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Big Sandy MT
 48.18°N 110.11°W (Elev. 2759 ft)
Last Update:
8:43 pm MDT Aug 17, 2025
Forecast Valid:
9pm MDT Aug 17, 2025-6pm MDT Aug 24, 2025
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation