National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Heavy Rainfall in the Southern Plains and Mississippi Valley; Thunderstorms in Eastern Colorado on Thursday

A multiple day heavy rainfall event will begin to set up from the Southern Plains into the Mississippi Valley Thursday, peaking in intensity over the holiday weekend. Widely scattered thunderstorms are expected to develop across eastern Colorado Thursday afternoon and evening. Large hail will be the primary hazard. Read More >

Current conditions at

Granby-Grand County Airport (KGNB)

Lat: 40.09°NLon: 105.92°WElev: 8207ft.

Partly Cloudy

36°F

2°C

Humidity 86%
Wind Speed Calm
Barometer 30.24 in
Dewpoint 33°F (1°C)
Visibility 10.00 mi
Last update 20 May 10:15 pm MDT
Extended Forecast for

Saint Marys Glacier CO

  • Tonight

    Tonight: Mostly clear, with a low around 22. West southwest wind 5 to 8 mph.

    Low: 22 °F

    Mostly Clear

  • Thursday

    Thursday: A 50 percent chance of snow showers after noon. Some thunder is also possible. Mostly sunny, with a high near 44. West southwest wind 7 to 11 mph, with gusts as high as 18 mph. Little or no snow accumulation expected.

    High: 44 °F

    Mostly Sunny
    then Chance
    Snow Showers

  • Thursday Night

    Thursday Night: A 50 percent chance of snow showers. Some thunder is also possible. Mostly cloudy, with a low around 25. West wind 6 to 9 mph, with gusts as high as 22 mph. New snow accumulation of less than one inch possible.

    Low: 25 °F

    Chance Snow
    Showers

  • Friday

    Friday: A 30 percent chance of snow showers, mainly after noon. Some thunder is also possible. Partly sunny, with a high near 43. West wind 8 to 14 mph, with gusts as high as 26 mph. New snow accumulation of less than a half inch possible.

    High: 43 °F

    Chance Snow
    Showers

  • Friday Night

    Friday Night: A 30 percent chance of snow showers, mainly before midnight. Some thunder is also possible. Mostly cloudy, with a low around 28. Light west southwest wind becoming west 5 to 10 mph after midnight. Winds could gust as high as 21 mph.

    Low: 28 °F

    Chance Snow
    Showers

  • Saturday

    Saturday: A 20 percent chance of snow showers after noon. Some thunder is also possible. Mostly sunny, with a high near 47. Breezy.

    High: 47 °F

    Breezy.
    Mostly Sunny
    then Slight
    Chance Snow
    Showers

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 31. Breezy.

    Low: 31 °F

    Partly Cloudy
    then Mostly
    Clear and
    Breezy

  • Sunday

    Sunday: Sunny, with a high near 58. Breezy.

    High: 58 °F

    Sunny and
    Breezy then
    Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 36.

    Low: 36 °F

    Mostly Clear

Detailed Forecast

Tonight
Mostly clear, with a low around 22. West southwest wind 5 to 8 mph.
Thursday
A 50 percent chance of snow showers after noon. Some thunder is also possible. Mostly sunny, with a high near 44. West southwest wind 7 to 11 mph, with gusts as high as 18 mph. Little or no snow accumulation expected.
Thursday Night
A 50 percent chance of snow showers. Some thunder is also possible. Mostly cloudy, with a low around 25. West wind 6 to 9 mph, with gusts as high as 22 mph. New snow accumulation of less than one inch possible.
Friday
A 30 percent chance of snow showers, mainly after noon. Some thunder is also possible. Partly sunny, with a high near 43. West wind 8 to 14 mph, with gusts as high as 26 mph. New snow accumulation of less than a half inch possible.
Friday Night
A 30 percent chance of snow showers, mainly before midnight. Some thunder is also possible. Mostly cloudy, with a low around 28. Light west southwest wind becoming west 5 to 10 mph after midnight. Winds could gust as high as 21 mph.
Saturday
A 20 percent chance of snow showers after noon. Some thunder is also possible. Mostly sunny, with a high near 47. Breezy.
Saturday Night
Mostly clear, with a low around 31. Breezy.
Sunday
Sunny, with a high near 58. Breezy.
Sunday Night
Mostly clear, with a low around 36.
Memorial Day
Showers likely and possibly a thunderstorm after noon. Mostly sunny, with a high near 61.
Monday Night
A slight chance of showers and thunderstorms. Partly cloudy, with a low around 39.
Tuesday
Showers likely and possibly a thunderstorm. Partly sunny, with a high near 57.
Tuesday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 38.
Wednesday
Showers likely and possibly a thunderstorm. Partly sunny, with a high near 55.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Saint Marys Glacier CO
 39.82°N 105.63°W (Elev. 10735 ft)
Last Update:
12:46 pm MDT May 20, 2026
Forecast Valid:
10pm MDT May 20, 2026-6pm MDT May 27, 2026
 
Forecast Discussion
 
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Additional Resources

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Hourly Weather Forecast

National Digital Forecast Database

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation