National Weather Service Forecast for: Helena MT
Issued by: National Weather Service Great Falls, MT
Updated: 12:31 am MDT Aug 20, 2026
 
Overnight

Overnight: Mostly clear, with a low around 55. Light southwest wind.
Mostly Clear

 Thursday

Thursday: Sunny, with a high near 92. Calm wind becoming west northwest 5 to 9 mph in the afternoon. Winds could gust as high as 18 mph.
Sunny

 Thursday
Night
Thursday Night: Partly cloudy, with a low around 58. North northwest wind 5 to 9 mph becoming light and variable.
Partly Cloudy

 Friday

Friday: Mostly sunny, with a high near 91. Calm wind becoming north northeast around 6 mph in the afternoon.
Mostly Sunny

 Friday
Night
Friday Night: Mostly cloudy, with a low around 60. North northwest wind around 6 mph becoming calm after midnight.
Mostly Cloudy

 Saturday

Saturday: A chance of showers between noon and 3pm, then a chance of showers and thunderstorms after 3pm. Partly sunny, with a high near 89. Calm wind becoming southwest 5 to 7 mph in the afternoon. Chance of precipitation is 30%.
Partly Sunny
then Chance
T-storms
 Saturday
Night
Saturday Night: A chance of showers and thunderstorms before 9pm, then a chance of showers between 9pm and midnight. Mostly cloudy, with a low around 58. West wind around 6 mph becoming south in the evening. Chance of precipitation is 30%.
Chance
Showers then
Mostly Cloudy
 Sunday

Sunday: A chance of showers and thunderstorms after noon. Mostly sunny, with a high near 85. Light south southwest wind becoming west 8 to 13 mph in the afternoon. Winds could gust as high as 25 mph.
Mostly Sunny
then Chance
T-storms
 Sunday
Night
Sunday Night: Mostly clear, with a low around 54.
Mostly Clear
Lo 55 °F Hi 92 °F Lo 58 °F Hi 91 °F Lo 60 °F Hi 89 °F Lo 58 °F Hi 85 °F Lo 54 °F

 

Overnight
 
 Mostly clear, with a low around 55. Light southwest wind.
Thursday
 
 Sunny, with a high near 92. Calm wind becoming west northwest 5 to 9 mph in the afternoon. Winds could gust as high as 18 mph.
Thursday Night
 
 Partly cloudy, with a low around 58. North northwest wind 5 to 9 mph becoming light and variable.
Friday
 
 Mostly sunny, with a high near 91. Calm wind becoming north northeast around 6 mph in the afternoon.
Friday Night
 
 Mostly cloudy, with a low around 60. North northwest wind around 6 mph becoming calm after midnight.
Saturday
 
 A chance of showers between noon and 3pm, then a chance of showers and thunderstorms after 3pm. Partly sunny, with a high near 89. Calm wind becoming southwest 5 to 7 mph in the afternoon. Chance of precipitation is 30%.
Saturday Night
 
 A chance of showers and thunderstorms before 9pm, then a chance of showers between 9pm and midnight. Mostly cloudy, with a low around 58. West wind around 6 mph becoming south in the evening. Chance of precipitation is 30%.
Sunday
 
 A chance of showers and thunderstorms after noon. Mostly sunny, with a high near 85. Light south southwest wind becoming west 8 to 13 mph in the afternoon. Winds could gust as high as 25 mph.
Sunday Night
 
 Mostly clear, with a low around 54.
Monday
 
 Sunny, with a high near 83.
Monday Night
 
 Partly cloudy, with a low around 55.
Tuesday
 
 Mostly sunny, with a high near 84.
Tuesday Night
 
 A slight chance of showers and thunderstorms. Mostly cloudy, with a low around 55.
Wednesday
 
 A slight chance of showers and thunderstorms. Mostly sunny, with a high near 84.

 

Forecast from NOAA-NWS for Helena MT.