National Weather Service Forecast for: Lewistown MT
Issued by: National Weather Service Great Falls, MT
Updated: 12:32 pm MDT May 4, 2026
 
This
Afternoon
This Afternoon: A 40 percent chance of showers. Mostly cloudy, with a high near 49. Northwest wind 18 to 21 mph, with gusts as high as 30 mph.
Chance
Showers

 Tonight

Tonight: A slight chance of rain and snow showers before 11pm, then a slight chance of snow showers between 11pm and midnight. Mostly cloudy, with a low around 28. North northwest wind 13 to 18 mph becoming light northwest. Winds could gust as high as 29 mph. Chance of precipitation is 20%.
Slight Chance
Rain/Snow
then Mostly
Cloudy
 Tuesday

Tuesday: A 40 percent chance of snow showers, mainly after 11am. Partly sunny, with a high near 47. North northwest wind 5 to 10 mph increasing to 15 to 20 mph in the afternoon. Winds could gust as high as 28 mph. Little or no snow accumulation expected.
Chance Snow
Showers

 Tuesday
Night
Tuesday Night: Partly cloudy, with a low around 24. North northwest wind 6 to 11 mph becoming light and variable after midnight. Winds could gust as high as 22 mph.
Partly Cloudy

 Wednesday

Wednesday: Sunny, with a high near 59. Light and variable wind becoming west northwest 5 to 7 mph in the afternoon.
Sunny

 Wednesday
Night
Wednesday Night: Mostly cloudy, with a low around 40. Northwest wind 6 to 8 mph becoming south in the evening.
Mostly Cloudy

 Thursday

Thursday: A chance of showers, then showers likely and possibly a thunderstorm after noon. Mostly cloudy, with a high near 63. West southwest wind 7 to 15 mph, with gusts as high as 25 mph. Chance of precipitation is 70%.
Chance
Showers then
Showers
Likely
 Thursday
Night
Thursday Night: A chance of rain before midnight. Mostly cloudy, with a low around 40. West northwest wind 5 to 11 mph becoming southwest after midnight. Winds could gust as high as 22 mph.
Chance Rain
then Mostly
Cloudy
 Friday

Friday: A chance of showers and thunderstorms after noon. Partly sunny, with a high near 67.
Partly Sunny
then Chance
Showers
Hi 49 °F Lo 28 °F Hi 47 °F Lo 24 °F Hi 59 °F Lo 40 °F Hi 63 °F Lo 40 °F Hi 67 °F

 

This Afternoon
 
 A 40 percent chance of showers. Mostly cloudy, with a high near 49. Northwest wind 18 to 21 mph, with gusts as high as 30 mph.
Tonight
 
 A slight chance of rain and snow showers before 11pm, then a slight chance of snow showers between 11pm and midnight. Mostly cloudy, with a low around 28. North northwest wind 13 to 18 mph becoming light northwest. Winds could gust as high as 29 mph. Chance of precipitation is 20%.
Tuesday
 
 A 40 percent chance of snow showers, mainly after 11am. Partly sunny, with a high near 47. North northwest wind 5 to 10 mph increasing to 15 to 20 mph in the afternoon. Winds could gust as high as 28 mph. Little or no snow accumulation expected.
Tuesday Night
 
 Partly cloudy, with a low around 24. North northwest wind 6 to 11 mph becoming light and variable after midnight. Winds could gust as high as 22 mph.
Wednesday
 
 Sunny, with a high near 59. Light and variable wind becoming west northwest 5 to 7 mph in the afternoon.
Wednesday Night
 
 Mostly cloudy, with a low around 40. Northwest wind 6 to 8 mph becoming south in the evening.
Thursday
 
 A chance of showers, then showers likely and possibly a thunderstorm after noon. Mostly cloudy, with a high near 63. West southwest wind 7 to 15 mph, with gusts as high as 25 mph. Chance of precipitation is 70%.
Thursday Night
 
 A chance of rain before midnight. Mostly cloudy, with a low around 40. West northwest wind 5 to 11 mph becoming southwest after midnight. Winds could gust as high as 22 mph.
Friday
 
 A chance of showers and thunderstorms after noon. Partly sunny, with a high near 67.
Friday Night
 
 A chance of showers and thunderstorms before midnight, then a chance of rain after midnight. Mostly cloudy, with a low around 43.
Saturday
 
 Rain likely. Mostly cloudy, with a high near 60.
Saturday Night
 
 A chance of rain. Mostly cloudy, with a low around 38.
Sunday
 
 A slight chance of rain. Mostly sunny, with a high near 66.

 

Forecast from NOAA-NWS for Lewistown MT.