National Weather Service Forecast for: Longmont CO
Issued by: National Weather Service Denver-Boulder, CO
Updated: 12:46 pm MDT Sep 12, 2026
 
Tonight

Tonight: Mostly clear, with a low around 57. Light and variable wind.
Mostly Clear

Sunday

Sunday: A chance of showers between 2pm and 3pm, then a chance of showers and thunderstorms after 3pm.  Increasing clouds, with a high near 92. Calm wind becoming southeast 5 to 9 mph in the afternoon. Winds could gust as high as 15 mph.  Chance of precipitation is 30%.
Sunny then
Chance
Showers
Sunday
Night
Sunday Night: A chance of showers and thunderstorms.  Mostly cloudy, with a low around 62. West wind around 6 mph becoming calm  after midnight.  Chance of precipitation is 30%.
Chance
Showers

Monday

Monday: A 20 percent chance of showers and thunderstorms after noon.  Partly sunny, with a high near 87. Calm wind becoming west 5 to 9 mph in the afternoon. Winds could gust as high as 15 mph.
Partly Sunny
then Slight
Chance
T-storms
Monday
Night
Monday Night: A slight chance of showers and thunderstorms, then a chance of showers after 9pm.  Mostly cloudy, with a low around 54. West northwest wind 5 to 8 mph becoming calm.  Chance of precipitation is 30%.
Slight Chance
T-storms then
Chance
Showers
Tuesday

Tuesday: A slight chance of showers, then a chance of showers and thunderstorms after noon.  Partly sunny, with a high near 75. Chance of precipitation is 50%.
Slight Chance
Showers then
Chance
Showers
Tuesday
Night
Tuesday Night: A 50 percent chance of showers and thunderstorms before midnight.  Mostly cloudy, with a low around 53.
Chance
Showers then
Partly Cloudy
Wednesday

Wednesday: A chance of showers and thunderstorms after noon.  Mostly sunny, with a high near 82.
Mostly Sunny
then Chance
T-storms
Wednesday
Night
Wednesday Night: A chance of showers and thunderstorms before midnight, then a slight chance of showers.  Mostly cloudy, with a low around 53.
Chance
Showers

Lo 57 °F Hi 92 °F Lo 62 °F Hi 87 °F Lo 54 °F Hi 75 °F Lo 53 °F Hi 82 °F Lo 53 °F

 

Tonight
 
Mostly clear, with a low around 57. Light and variable wind.
Sunday
 
A chance of showers between 2pm and 3pm, then a chance of showers and thunderstorms after 3pm. Increasing clouds, with a high near 92. Calm wind becoming southeast 5 to 9 mph in the afternoon. Winds could gust as high as 15 mph. Chance of precipitation is 30%.
Sunday Night
 
A chance of showers and thunderstorms. Mostly cloudy, with a low around 62. West wind around 6 mph becoming calm after midnight. Chance of precipitation is 30%.
Monday
 
A 20 percent chance of showers and thunderstorms after noon. Partly sunny, with a high near 87. Calm wind becoming west 5 to 9 mph in the afternoon. Winds could gust as high as 15 mph.
Monday Night
 
A slight chance of showers and thunderstorms, then a chance of showers after 9pm. Mostly cloudy, with a low around 54. West northwest wind 5 to 8 mph becoming calm. Chance of precipitation is 30%.
Tuesday
 
A slight chance of showers, then a chance of showers and thunderstorms after noon. Partly sunny, with a high near 75. Chance of precipitation is 50%.
Tuesday Night
 
A 50 percent chance of showers and thunderstorms before midnight. Mostly cloudy, with a low around 53.
Wednesday
 
A chance of showers and thunderstorms after noon. Mostly sunny, with a high near 82.
Wednesday Night
 
A chance of showers and thunderstorms before midnight, then a slight chance of showers. Mostly cloudy, with a low around 53.
Thursday
 
A slight chance of showers, then a chance of showers and thunderstorms after noon. Partly sunny, with a high near 76.
Thursday Night
 
A chance of showers. Mostly cloudy, with a low around 52.
Friday
 
A chance of showers and thunderstorms. Mostly sunny, with a high near 79.
Friday Night
 
A slight chance of showers. Partly cloudy, with a low around 51.
Saturday
 
Mostly sunny, with a high near 78.

 

Forecast from NOAA-NWS for Longmont CO.