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

Dangerous Heat and Heavy Rainfall into the Weekend

Hot temperatures and high humidity are forecast to continue across the mid-Mississippi Valley into this weekend. Heat Advisories remain in effect. Heavy to excessive rainfall occurring at times through the weekend could bring areas of flooding to parts of the northern Rockies, upper Midwest, central Great Lakes, and southern New England. Read More >

Current conditions at

Lewistown Divide MT-200 MP 90.3 (MTLEW)

Lat: 47.07579°NLon: 109.26247°WElev: 4723.0ft.

unknown precip

46°F

8°C

Humidity 99%
Wind Speed WNW 1 MPH
Barometer NA
Dewpoint 46°F (8°C)
Visibility NA
Last update 19 Sep 10:30 PM MDT
Extended Forecast for

Lewistown MT

  • Tonight

    Tonight: Rain likely, mainly before 4am. Patchy fog after 2am. Otherwise, cloudy, with a low around 46. Calm wind. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.

    Low: 46 °F

    Rain Likely
    and Patchy
    Fog

  • Sunday

    Sunday: A 30 percent chance of rain, mainly before 9am. Patchy fog before 10am. Otherwise, cloudy, then gradually becoming mostly sunny, with a high near 66. Calm wind becoming east southeast around 6 mph in the afternoon.

    High: 66 °F

    Chance Rain
    and Patchy
    Fog then
    Mostly Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 44. Southeast wind 5 to 7 mph.

    Low: 44 °F

    Partly Cloudy

  • Monday

    Monday: Sunny, with a high near 75. Southeast wind around 5 mph becoming calm in the morning.

    High: 75 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 47. Light south wind becoming south southeast 5 to 9 mph in the evening.

    Low: 47 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 79. Light and variable wind.

    High: 79 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 50. Calm wind becoming south southeast 5 to 8 mph.

    Low: 50 °F

    Partly Cloudy

  • Wednesday

    Wednesday: Mostly sunny, with a high near 79. Light west southwest wind.

    High: 79 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 51.

    Low: 51 °F

    Partly Cloudy

Detailed Forecast

Tonight
Rain likely, mainly before 4am. Patchy fog after 2am. Otherwise, cloudy, with a low around 46. Calm wind. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.
Sunday
A 30 percent chance of rain, mainly before 9am. Patchy fog before 10am. Otherwise, cloudy, then gradually becoming mostly sunny, with a high near 66. Calm wind becoming east southeast around 6 mph in the afternoon.
Sunday Night
Partly cloudy, with a low around 44. Southeast wind 5 to 7 mph.
Monday
Sunny, with a high near 75. Southeast wind around 5 mph becoming calm in the morning.
Monday Night
Mostly clear, with a low around 47. Light south wind becoming south southeast 5 to 9 mph in the evening.
Tuesday
Sunny, with a high near 79. Light and variable wind.
Tuesday Night
Partly cloudy, with a low around 50. Calm wind becoming south southeast 5 to 8 mph.
Wednesday
Mostly sunny, with a high near 79. Light west southwest wind.
Wednesday Night
Partly cloudy, with a low around 51.
Thursday
Sunny, with a high near 80.
Thursday Night
Mostly clear, with a low around 52.
Friday
Mostly sunny, with a high near 79.
Friday Night
Partly cloudy, with a low around 48.
Saturday
A slight chance of rain. Partly sunny, with a high near 67.
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ABOUT THIS FORECAST

 
Point Forecast:
Lewistown MT
 47.07°N 109.43°W (Elev. 3898 ft)
Last Update:
8:41 pm MDT Sep 19, 2026
Forecast Valid:
10pm MDT Sep 19, 2026-6pm MDT Sep 26, 2026
 
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Additional Resources

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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