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

Tracking Winter Weather and Frigid Temperatures Through This Weekend

A clipper storm will move across the Great Lakes through this weekend with periods of light snow, gusty winds, and lake effect snow bands which could make for hazardous travel at times. A frigid airmass will spread eastward behind this storm into the Midwest and Eastern U.S. through the weekend. Read More >

Hazardous Weather Conditions

Current conditions at

San Marcos, San Marcos Municipal Airport (KHYI)

Lat: 29.89°NLon: 97.86°WElev: 597ft.

Fair

41°F

5°C

Humidity 25%
Wind Speed N 10 mph
Barometer 30.24 in (1024.1 mb)
Dewpoint 8°F (-13°C)
Visibility 10.00 mi
Wind Chill35°F (2°C)
Last update 17 Jan 6:56 am CST
Extended Forecast for

San Marcos TX

Red Flag Warning January 17, 10:00am until January 17, 08:00pm
Click here for hazard details and duration
Red Flag Warning

  • Today

    Today: Sunny, with a high near 56. North northeast wind 10 to 15 mph, with gusts as high as 30 mph.

    High: 56 °F

    Sunny

  • Tonight

    Tonight: Mostly clear, with a low around 29. North northeast wind 5 to 15 mph becoming northwest after midnight. Winds could gust as high as 25 mph.

    Low: 29 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny, with a high near 61. Northwest wind 5 to 10 mph becoming south southwest in the afternoon.

    High: 61 °F

    Sunny

  • Sunday Night

    Sunday Night: Clear, with a low around 34. South southwest wind around 5 mph.

    Low: 34 °F

    Clear

  • M.L.King Day

    M.L.King Day: Sunny, with a high near 64. West southwest wind around 5 mph becoming east southeast in the afternoon.

    High: 64 °F

    Sunny

  • Monday Night

    Monday Night: Mostly cloudy, with a low around 40. East wind around 5 mph becoming north northeast after midnight.

    Low: 40 °F

    Mostly Cloudy

  • Tuesday

    Tuesday: Mostly cloudy, with a high near 59. North northeast wind around 5 mph becoming southeast in the afternoon.

    High: 59 °F

    Mostly Cloudy

  • Tuesday Night

    Tuesday Night: A 20 percent chance of showers after midnight. Cloudy, with a low around 50. South southeast wind around 5 mph.

    Low: 50 °F

    Cloudy then
    Slight Chance
    Showers

  • Wednesday

    Wednesday: A 30 percent chance of showers. Mostly cloudy, with a high near 65. South wind around 5 mph.

    High: 65 °F

    Chance
    Showers

Detailed Forecast

Today
Sunny, with a high near 56. North northeast wind 10 to 15 mph, with gusts as high as 30 mph.
Tonight
Mostly clear, with a low around 29. North northeast wind 5 to 15 mph becoming northwest after midnight. Winds could gust as high as 25 mph.
Sunday
Sunny, with a high near 61. Northwest wind 5 to 10 mph becoming south southwest in the afternoon.
Sunday Night
Clear, with a low around 34. South southwest wind around 5 mph.
M.L.King Day
Sunny, with a high near 64. West southwest wind around 5 mph becoming east southeast in the afternoon.
Monday Night
Mostly cloudy, with a low around 40. East wind around 5 mph becoming north northeast after midnight.
Tuesday
Mostly cloudy, with a high near 59. North northeast wind around 5 mph becoming southeast in the afternoon.
Tuesday Night
A 20 percent chance of showers after midnight. Cloudy, with a low around 50. South southeast wind around 5 mph.
Wednesday
A 30 percent chance of showers. Mostly cloudy, with a high near 65. South wind around 5 mph.
Wednesday Night
Mostly cloudy, with a low around 50.
Thursday
Mostly sunny, with a high near 67.
Thursday Night
Partly cloudy, with a low around 42.
Friday
Mostly cloudy, with a high near 61.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
San Marcos TX
 29.88°N 97.94°W (Elev. 577 ft)
Last Update:
5:42 am CST Jan 17, 2026
Forecast Valid:
7am CST Jan 17, 2026-6pm CST Jan 23, 2026
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation