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

Atmospheric River Bringing Heavy Rain to Southern California and Heavy Snow to the Sierra Nevadas

A strong atmospheric river will continue heavy rain over southern California through Friday. The heaviest rainfall is ongoing today in the Los Angeles Basin. Flash and urban flooding is possible. A prolonged heavy snowfall has begun over the Sierra Nevada Mountains and will continue through Friday. Travel will become increasingly difficult over the passes due to snow and strong winds. Read More >

Current conditions at

Lewistown, Lewistown Municipal Airport (KLWT)

Lat: 47.04917°NLon: 109.46639°WElev: 4167.0ft.

Overcast

43°F

6°C

Humidity 52%
Wind Speed SW 12 MPH
Barometer 29.68 in (1005.08 mb)
Dewpoint 26°F (-3°C)
Visibility 10.00 mi
Wind Chill37°F (3°C)
Last update 26 Dec 02:35 AM MST
Extended Forecast for

Lewistown MT

  • Overnight

    Overnight: A slight chance of showers between 3am and 4am. Mostly cloudy, with a low around 37. South southwest wind around 11 mph. Chance of precipitation is 10%.

    Low: 37 °F

    Slight Chance
    Showers

  • Friday

    Friday: Mostly sunny, with a high near 53. Breezy, with a south southwest wind 13 to 23 mph, with gusts as high as 32 mph.

    High: 53 °F

    Mostly Sunny
    then Mostly
    Sunny and
    Breezy

  • Friday Night

    Friday Night: Increasing clouds, with a low around 12. Southwest wind 9 to 17 mph, with gusts as high as 24 mph.

    Low: 12 °F

    Increasing
    Clouds

  • Saturday

    Saturday: Snow likely. Mostly cloudy, with a high near 26. Wind chill values as low as -15. Northwest wind 16 to 20 mph, with gusts as high as 29 mph. Chance of precipitation is 70%. New snow accumulation of less than one inch possible.

    High: 26 °F

    Snow Likely

  • Saturday Night

    Saturday Night: Mostly cloudy, with a low around -5. West wind 13 to 18 mph decreasing to 7 to 12 mph after midnight. Winds could gust as high as 28 mph.

    Low: -5 °F

    Mostly Cloudy

  • Sunday

    Sunday: Mostly sunny, with a high near 26. West wind around 5 mph becoming calm in the morning.

    High: 26 °F

    Mostly Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 13. Calm wind becoming south southwest around 6 mph in the evening.

    Low: 13 °F

    Partly Cloudy

  • Monday

    Monday: Mostly sunny, with a high near 43. West wind around 6 mph.

    High: 43 °F

    Mostly Sunny

  • Monday Night

    Monday Night: Mostly cloudy, with a low around 26.

    Low: 26 °F

    Mostly Cloudy

Detailed Forecast

Overnight
A slight chance of showers between 3am and 4am. Mostly cloudy, with a low around 37. South southwest wind around 11 mph. Chance of precipitation is 10%.
Friday
Mostly sunny, with a high near 53. Breezy, with a south southwest wind 13 to 23 mph, with gusts as high as 32 mph.
Friday Night
Increasing clouds, with a low around 12. Southwest wind 9 to 17 mph, with gusts as high as 24 mph.
Saturday
Snow likely. Mostly cloudy, with a high near 26. Wind chill values as low as -15. Northwest wind 16 to 20 mph, with gusts as high as 29 mph. Chance of precipitation is 70%. New snow accumulation of less than one inch possible.
Saturday Night
Mostly cloudy, with a low around -5. West wind 13 to 18 mph decreasing to 7 to 12 mph after midnight. Winds could gust as high as 28 mph.
Sunday
Mostly sunny, with a high near 26. West wind around 5 mph becoming calm in the morning.
Sunday Night
Partly cloudy, with a low around 13. Calm wind becoming south southwest around 6 mph in the evening.
Monday
Mostly sunny, with a high near 43. West wind around 6 mph.
Monday Night
Mostly cloudy, with a low around 26.
Tuesday
Partly sunny, with a high near 47.
Tuesday Night
Mostly cloudy, with a low around 27.
Wednesday
A slight chance of rain and snow. Mostly cloudy, with a high near 43.
Wednesday Night
A slight chance of rain and snow. Mostly cloudy, with a low around 22.
New Year's Day
A slight chance of snow. Mostly cloudy, with a high near 40.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Lewistown MT
 47.07°N 109.43°W (Elev. 3898 ft)
Last Update:
1:22 am MST Dec 26, 2025
Forecast Valid:
2am MST Dec 26, 2025-6pm MST Jan 1, 2026
 
Forecast Discussion
 
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Additional Resources

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