Thunderstorms and Heavy Rain in the Mid-South; Heat Continues in the Southeast and Southwest

Severe thunderstorms and heavy rain are expected across portions of the mid-Mississippi Valley into the Ohio Valley and portions of Arizona. Dangerous heat persists in the South and Southeast while building into the Southwest. Overnight lows will be so warm that, when combined with oppressive dew points, little-to-no relief from the scorching daytime highs will be available. Read More >

Current conditions at

Sieben I-15 MP 216 (MTSBN)

Lat: 46.88748267°NLon: 112.1111196°WElev: 4199.0ft.

NA

79°F

26°C

Humidity 25%
Wind Speed NW 10 MPH
Barometer NA
Dewpoint 40°F (4°C)
Visibility NA
Heat Index78°F (26°C)
Last update 18 Aug 07:45 PM MDT
Extended Forecast for

Marysville MT

  • Tonight

    Tonight: Mostly clear, with a low around 54. West wind 7 to 9 mph.

    Low: 54 °F

    Mostly Clear

  • Wednesday

    Wednesday: Patchy smoke before 7am. Sunny, with a high near 76. West southwest wind 7 to 10 mph, with gusts as high as 21 mph.

    High: 76 °F

    Patchy Smoke
    then Sunny

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 56. West southwest wind 6 to 9 mph, with gusts as high as 21 mph.

    Low: 56 °F

    Mostly Clear

  • Thursday

    Thursday: Sunny, with a high near 79. Calm wind becoming west 5 to 7 mph in the afternoon.

    High: 79 °F

    Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 58. Northwest wind 3 to 8 mph.

    Low: 58 °F

    Mostly Clear

  • Friday

    Friday: Mostly sunny, with a high near 79. Calm wind becoming east 5 to 7 mph in the afternoon.

    High: 79 °F

    Mostly Sunny

  • Friday Night

    Friday Night: A 20 percent chance of showers.  Mostly cloudy, with a low around 63. East northeast wind 5 to 7 mph becoming calm  after midnight.

    Low: 63 °F

    Slight Chance
    Showers

  • Saturday

    Saturday: A chance of showers and thunderstorms after noon.  Partly sunny, with a high near 77. South wind 3 to 8 mph.

    High: 77 °F

    Partly Sunny
    then Chance
    Showers

  • Saturday Night

    Saturday Night: A chance of showers and thunderstorms before midnight.  Partly cloudy, with a low around 57.

    Low: 57 °F

    Chance
    Showers then
    Mostly Clear

Detailed Forecast

Tonight
Mostly clear, with a low around 54. West wind 7 to 9 mph.
Wednesday
Patchy smoke before 7am. Sunny, with a high near 76. West southwest wind 7 to 10 mph, with gusts as high as 21 mph.
Wednesday Night
Mostly clear, with a low around 56. West southwest wind 6 to 9 mph, with gusts as high as 21 mph.
Thursday
Sunny, with a high near 79. Calm wind becoming west 5 to 7 mph in the afternoon.
Thursday Night
Mostly clear, with a low around 58. Northwest wind 3 to 8 mph.
Friday
Mostly sunny, with a high near 79. Calm wind becoming east 5 to 7 mph in the afternoon.
Friday Night
A 20 percent chance of showers. Mostly cloudy, with a low around 63. East northeast wind 5 to 7 mph becoming calm after midnight.
Saturday
A chance of showers and thunderstorms after noon. Partly sunny, with a high near 77. South wind 3 to 8 mph.
Saturday Night
A chance of showers and thunderstorms before midnight. Partly cloudy, with a low around 57.
Sunday
Sunny, with a high near 72.
Sunday Night
Mostly clear, with a low around 54.
Monday
Sunny, with a high near 75.
Monday Night
Partly cloudy, with a low around 57.
Tuesday
A slight chance of showers and thunderstorms. Mostly sunny, with a high near 76.
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ABOUT THIS FORECAST

 
Point Forecast:
Marysville MT
 46.75°N 112.29°W (Elev. 5456 ft)
12:31 pm MDT Aug 18, 2026
8pm MDT Aug 18, 2026-6pm MDT Aug 25, 2026
 
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Additional Resources

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Hourly Weather Forecast

National Digital Forecast Database