National Weather Service Forecast for: Lewistown MT
Issued by: National Weather Service Great Falls, MT
Updated: 9:17 pm MST Dec 4, 2025
 
Overnight

Overnight: A 50 percent chance of snow, mainly after 4am. Mostly cloudy, with a low around 21. West wind around 10 mph, with gusts as high as 18 mph. Total nighttime snow accumulation of less than a half inch possible.
Chance Snow

 Friday

Friday: A chance of snow before 11am, then a slight chance of snow after 4pm. Cloudy, then gradually becoming mostly sunny, with a high near 35. West wind 5 to 7 mph becoming light and variable. Chance of precipitation is 40%. New snow accumulation of less than a half inch possible.
Chance Snow

 Friday
Night
Friday Night: Snow, mainly after 8pm. Low around 19. Southeast wind 7 to 9 mph becoming west after midnight. Winds could gust as high as 23 mph. Chance of precipitation is 90%. New snow accumulation of 1 to 2 inches possible.
Snow

 Saturday

Saturday: Snow likely, mainly before 11am. Cloudy, with a high near 33. West northwest wind 3 to 8 mph. Chance of precipitation is 70%. New snow accumulation of around an inch possible.
Snow Likely
then Chance
Snow
 Saturday
Night
Saturday Night: A 30 percent chance of snow before 11pm. Mostly cloudy, with a low around 20. West southwest wind 5 to 11 mph, with gusts as high as 21 mph. New snow accumulation of less than a half inch possible.
Chance Snow
then Mostly
Cloudy
 Sunday

Sunday: Partly sunny, with a high near 40. West wind around 11 mph, with gusts as high as 22 mph.
Partly Sunny

 Sunday
Night
Sunday Night: Mostly cloudy, with a low around 27. West southwest wind 14 to 18 mph, with gusts as high as 31 mph.
Mostly Cloudy

 Monday

Monday: Mostly sunny, with a high near 41. West wind 14 to 18 mph, with gusts as high as 32 mph.
Mostly Sunny

 Monday
Night
Monday Night: A slight chance of rain and snow after 11pm. Mostly cloudy, with a low around 28.
Slight Chance
Rain/Snow
Lo 21 °F Hi 35 °F Lo 19 °F Hi 33 °F Lo 20 °F Hi 40 °F Lo 27 °F Hi 41 °F Lo 28 °F

 

Overnight
 
 A 50 percent chance of snow, mainly after 4am. Mostly cloudy, with a low around 21. West wind around 10 mph, with gusts as high as 18 mph. Total nighttime snow accumulation of less than a half inch possible.
Friday
 
 A chance of snow before 11am, then a slight chance of snow after 4pm. Cloudy, then gradually becoming mostly sunny, with a high near 35. West wind 5 to 7 mph becoming light and variable. Chance of precipitation is 40%. New snow accumulation of less than a half inch possible.
Friday Night
 
 Snow, mainly after 8pm. Low around 19. Southeast wind 7 to 9 mph becoming west after midnight. Winds could gust as high as 23 mph. Chance of precipitation is 90%. New snow accumulation of 1 to 2 inches possible.
Saturday
 
 Snow likely, mainly before 11am. Cloudy, with a high near 33. West northwest wind 3 to 8 mph. Chance of precipitation is 70%. New snow accumulation of around an inch possible.
Saturday Night
 
 A 30 percent chance of snow before 11pm. Mostly cloudy, with a low around 20. West southwest wind 5 to 11 mph, with gusts as high as 21 mph. New snow accumulation of less than a half inch possible.
Sunday
 
 Partly sunny, with a high near 40. West wind around 11 mph, with gusts as high as 22 mph.
Sunday Night
 
 Mostly cloudy, with a low around 27. West southwest wind 14 to 18 mph, with gusts as high as 31 mph.
Monday
 
 Mostly sunny, with a high near 41. West wind 14 to 18 mph, with gusts as high as 32 mph.
Monday Night
 
 A slight chance of rain and snow after 11pm. Mostly cloudy, with a low around 28.
Tuesday
 
 A chance of rain before 2pm, then a chance of rain and snow. Mostly cloudy, with a high near 46. Breezy.
Tuesday Night
 
 Rain and snow likely. Mostly cloudy, with a low around 25.
Wednesday
 
 A chance of rain and snow. Partly sunny, with a high near 40.
Wednesday Night
 
 A chance of rain and snow. Mostly cloudy, with a low around 24.
Thursday
 
 A chance of snow. Mostly cloudy, with a high near 42.

 

Forecast from NOAA-NWS for Lewistown MT.