National Weather Service Forecast for: Lewistown MT
Issued by: National Weather Service Great Falls, MT
Updated: 12:41 pm MDT Jul 28, 2026
 
This
Afternoon
This Afternoon: Patchy smoke. Sunny, with a high near 94. Southeast wind 3 to 6 mph.
Patchy Smoke

 Tonight

Tonight: A 20 percent chance of showers before 8pm. Patchy smoke. Mostly clear, with a low around 57. East southeast wind around 5 mph becoming calm after midnight.
Slight Chance
Showers then
Patchy Smoke
 Wednesday

Wednesday: Areas of smoke. Sunny, with a high near 91. Calm wind becoming west around 5 mph in the afternoon.
Areas Smoke

 Wednesday
Night
Wednesday Night: A 20 percent chance of showers and thunderstorms before 7pm. Patchy smoke before 3am, then patchy smoke after 4am. Mostly cloudy, with a low around 57. East wind around 6 mph becoming light and variable after midnight.
Slight Chance
T-storms then
Patchy Smoke
 Thursday

Thursday: A slight chance of showers between noon and 3pm, then a slight chance of showers and thunderstorms after 3pm. Mostly sunny, with a high near 92. Calm wind becoming north northwest around 5 mph in the afternoon. Chance of precipitation is 20%.
Mostly Sunny
then Slight
Chance
T-storms
 Thursday
Night
Thursday Night: A slight chance of showers and thunderstorms before midnight, then a chance of showers between midnight and 3am, then a chance of showers and thunderstorms after 3am. Partly cloudy, with a low around 57. Northeast wind 5 to 8 mph becoming south after midnight. Chance of precipitation is 30%.
Slight Chance
T-storms then
Chance
Showers
 Friday

Friday: Sunny, with a high near 94. Calm wind becoming north northwest 5 to 7 mph in the afternoon.
Sunny

 Friday
Night
Friday Night: Clear, with a low around 60. North wind 5 to 7 mph becoming south southeast after midnight.
Clear

 Saturday

Saturday: Sunny and hot, with a high near 99.
Hot
Hi 94 °F Lo 57 °F Hi 91 °F Lo 57 °F Hi 92 °F Lo 57 °F Hi 94 °F Lo 60 °F Hi 99 °F

Air Quality Alert
 

This Afternoon
 
 Patchy smoke. Sunny, with a high near 94. Southeast wind 3 to 6 mph.
Tonight
 
 A 20 percent chance of showers before 8pm. Patchy smoke. Mostly clear, with a low around 57. East southeast wind around 5 mph becoming calm after midnight.
Wednesday
 
 Areas of smoke. Sunny, with a high near 91. Calm wind becoming west around 5 mph in the afternoon.
Wednesday Night
 
 A 20 percent chance of showers and thunderstorms before 7pm. Patchy smoke before 3am, then patchy smoke after 4am. Mostly cloudy, with a low around 57. East wind around 6 mph becoming light and variable after midnight.
Thursday
 
 A slight chance of showers between noon and 3pm, then a slight chance of showers and thunderstorms after 3pm. Mostly sunny, with a high near 92. Calm wind becoming north northwest around 5 mph in the afternoon. Chance of precipitation is 20%.
Thursday Night
 
 A slight chance of showers and thunderstorms before midnight, then a chance of showers between midnight and 3am, then a chance of showers and thunderstorms after 3am. Partly cloudy, with a low around 57. Northeast wind 5 to 8 mph becoming south after midnight. Chance of precipitation is 30%.
Friday
 
 Sunny, with a high near 94. Calm wind becoming north northwest 5 to 7 mph in the afternoon.
Friday Night
 
 Clear, with a low around 60. North wind 5 to 7 mph becoming south southeast after midnight.
Saturday
 
 Sunny and hot, with a high near 99.
Saturday Night
 
 Mostly clear, with a low around 59.
Sunday
 
 Sunny, with a high near 88.
Sunday Night
 
 A chance of showers. Partly cloudy, with a low around 50.
Monday
 
 Mostly sunny, with a high near 74.

 

Forecast from NOAA-NWS for Lewistown MT.