National Weather Service Forecast for: Lewistown MT
Issued by: National Weather Service Great Falls, MT
Updated: 10:19 am MDT May 30, 2025
 
Tonight

Tonight: Mostly clear, with a low around 45. Northwest wind 5 to 10 mph becoming southeast after midnight.
Mostly Clear

 Saturday

Saturday: Sunny, with a high near 85. Southeast wind 6 to 9 mph.
Sunny

 Saturday
Night
Saturday Night: Mostly clear, with a low around 58. South wind 9 to 11 mph, with gusts as high as 18 mph.
Mostly Clear

 Sunday

Sunday: A 40 percent chance of showers and thunderstorms after noon. Mostly sunny, with a high near 76. Southwest wind 6 to 13 mph becoming north northwest in the afternoon. Winds could gust as high as 23 mph.
Sunny then
Chance
Showers
 Sunday
Night
Sunday Night: Showers and possibly a thunderstorm. Low around 46. North wind 6 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 90%.
Showers

 Monday

Monday: Showers, with thunderstorms also possible after noon. High near 57. North northwest wind 6 to 11 mph, with gusts as high as 21 mph. Chance of precipitation is 80%.
Showers

 Monday
Night
Monday Night: Showers likely, mainly before midnight. Mostly cloudy, with a low around 39. West northwest wind 6 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 60%.
Showers
Likely
 Tuesday

Tuesday: A chance of showers, with thunderstorms also possible after noon. Partly sunny, with a high near 62. West wind 6 to 8 mph becoming north northwest in the afternoon.
Chance
Showers
 Tuesday
Night
Tuesday Night: A slight chance of showers before midnight. Partly cloudy, with a low around 40.
Slight Chance
Showers then
Partly Cloudy
Lo 45 °F Hi 85 °F Lo 58 °F Hi 76 °F Lo 46 °F Hi 57 °F Lo 39 °F Hi 62 °F Lo 40 °F

 

Tonight
 
 Mostly clear, with a low around 45. Northwest wind 5 to 10 mph becoming southeast after midnight.
Saturday
 
 Sunny, with a high near 85. Southeast wind 6 to 9 mph.
Saturday Night
 
 Mostly clear, with a low around 58. South wind 9 to 11 mph, with gusts as high as 18 mph.
Sunday
 
 A 40 percent chance of showers and thunderstorms after noon. Mostly sunny, with a high near 76. Southwest wind 6 to 13 mph becoming north northwest in the afternoon. Winds could gust as high as 23 mph.
Sunday Night
 
 Showers and possibly a thunderstorm. Low around 46. North wind 6 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 90%.
Monday
 
 Showers, with thunderstorms also possible after noon. High near 57. North northwest wind 6 to 11 mph, with gusts as high as 21 mph. Chance of precipitation is 80%.
Monday Night
 
 Showers likely, mainly before midnight. Mostly cloudy, with a low around 39. West northwest wind 6 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 60%.
Tuesday
 
 A chance of showers, with thunderstorms also possible after noon. Partly sunny, with a high near 62. West wind 6 to 8 mph becoming north northwest in the afternoon.
Tuesday Night
 
 A slight chance of showers before midnight. Partly cloudy, with a low around 40.
Wednesday
 
 A chance of showers after noon. Mostly sunny, with a high near 67.
Wednesday Night
 
 A slight chance of showers. Partly cloudy, with a low around 44.
Thursday
 
 A slight chance of showers and thunderstorms. Mostly sunny, with a high near 71.
Thursday Night
 
 Partly cloudy, with a low around 47.
Friday
 
 A chance of showers and thunderstorms. Mostly sunny, with a high near 73.

 

Forecast from NOAA-NWS for Lewistown MT.