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

Prolonged Extreme Cold; Eastern U.S. Winter Storm

A powerful Arctic blast will bring dangerously cold, record low temperatures to the Gulf Coast, upper Ohio Valley, Mid-Atlantic, and Southeast U.S. into this weekend. A rapidly deepening storm centered just off the North Carolina coast Friday night through Saturday night will produce widespread heavy snow and wind from the southern Appalachians across the Carolinas and southern Virginia. Read More >

Hazardous Weather Conditions

Current conditions at

San Marcos, San Marcos Municipal Airport (KHYI)

Lat: 29.89°NLon: 97.86°WElev: 597ft.

Fair

48°F

9°C

Humidity 48%
Wind Speed N 20 mph
Barometer 30.25 in (1024.2 mb)
Dewpoint 29°F (-2°C)
Visibility 10.00 mi
Wind Chill41°F (5°C)
Last update 29 Jan 11:56 pm CST
Extended Forecast for

San Marcos TX

Cold Weather Advisory January 31, 03:00am until January 31, 10:00am
Click here for hazard details and duration
Cold Weather Advisory

  • Overnight

    Overnight: Partly cloudy, with a low around 36. North wind 10 to 15 mph, with gusts as high as 25 mph.

    Low: 36 °F

    Partly Cloudy

  • Friday

    Friday: Cloudy, then gradually becoming mostly sunny, with a high near 55. North wind 5 to 15 mph, with gusts as high as 25 mph.

    High: 55 °F

    Decreasing
    Clouds

  • Friday Night

    Friday Night: Mostly clear, with a low around 30. North northeast wind 5 to 10 mph, with gusts as high as 20 mph.

    Low: 30 °F

    Mostly Clear

  • Saturday

    Saturday: Sunny, with a high near 45. North northeast wind 5 to 15 mph, with gusts as high as 25 mph.

    High: 45 °F

    Sunny

  • Saturday Night

    Saturday Night: Clear, with a low around 22. Northeast wind around 5 mph becoming calm in the evening.

    Low: 22 °F

    Clear

  • Sunday

    Sunday: Sunny, with a high near 55. Calm wind becoming south southwest around 5 mph in the afternoon.

    High: 55 °F

    Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 36. West southwest wind around 5 mph.

    Low: 36 °F

    Mostly Clear

  • Monday

    Monday: Partly sunny, with a high near 65. South wind 5 to 10 mph, with gusts as high as 20 mph.

    High: 65 °F

    Partly Sunny

  • Monday Night

    Monday Night: Mostly cloudy, with a low around 53. South wind 5 to 10 mph.

    Low: 53 °F

    Mostly Cloudy

Detailed Forecast

Overnight
Partly cloudy, with a low around 36. North wind 10 to 15 mph, with gusts as high as 25 mph.
Friday
Cloudy, then gradually becoming mostly sunny, with a high near 55. North wind 5 to 15 mph, with gusts as high as 25 mph.
Friday Night
Mostly clear, with a low around 30. North northeast wind 5 to 10 mph, with gusts as high as 20 mph.
Saturday
Sunny, with a high near 45. North northeast wind 5 to 15 mph, with gusts as high as 25 mph.
Saturday Night
Clear, with a low around 22. Northeast wind around 5 mph becoming calm in the evening.
Sunday
Sunny, with a high near 55. Calm wind becoming south southwest around 5 mph in the afternoon.
Sunday Night
Mostly clear, with a low around 36. West southwest wind around 5 mph.
Monday
Partly sunny, with a high near 65. South wind 5 to 10 mph, with gusts as high as 20 mph.
Monday Night
Mostly cloudy, with a low around 53. South wind 5 to 10 mph.
Tuesday
Mostly cloudy, with a high near 71.
Tuesday Night
A 30 percent chance of showers. Mostly cloudy, with a low around 49.
Wednesday
Partly sunny, with a high near 64.
Wednesday Night
Partly cloudy, with a low around 40.
Thursday
Sunny, with a high near 62.
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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:
12:42 am CST Jan 30, 2026
Forecast Valid:
12am CST Jan 30, 2026-6pm CST Feb 5, 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