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

San Marcos, San Marcos Municipal Airport (KHYI)

Lat: 29.89°NLon: 97.86°WElev: 597ft.

Fair

45°F

7°C

Humidity 44%
Wind Speed S 5 mph
Barometer 30.27 in (1025.0 mb)
Dewpoint 24°F (-4°C)
Visibility 10.00 mi
Wind Chill42°F (6°C)
Last update 15 Dec 10:56 pm CST
Extended Forecast for

San Marcos TX

  • Tonight

    Tonight: Mostly cloudy, with a low around 41. South wind around 5 mph becoming calm after midnight.

    Low: 41 °F

    Mostly Cloudy

  • Tuesday

    Tuesday: Cloudy, with a high near 61. Calm wind becoming south around 5 mph in the morning.

    High: 61 °F

    Cloudy

  • Tuesday Night

    Tuesday Night: A chance of showers, with thunderstorms also possible after 3am. Patchy fog after 1am. Otherwise, cloudy, with a low around 55. South wind around 5 mph becoming calm. Chance of precipitation is 30%.

    Low: 55 °F

    Chance
    Showers and
    Patchy Fog

  • Wednesday

    Wednesday: A 20 percent chance of showers and thunderstorms. Patchy fog before noon. Otherwise, cloudy, with a high near 68. Calm wind becoming southeast around 5 mph in the afternoon.

    High: 68 °F

    Slight Chance
    T-storms and
    Patchy Fog

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 61. South wind 5 to 10 mph.

    Low: 61 °F

    Mostly Cloudy

  • Thursday

    Thursday: Mostly sunny, with a high near 78. South southwest wind 5 to 15 mph becoming north in the afternoon. Winds could gust as high as 20 mph.

    High: 78 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 44. North northeast wind 5 to 10 mph, with gusts as high as 20 mph.

    Low: 44 °F

    Mostly Clear

  • Friday

    Friday: Sunny, with a high near 68. North northeast wind around 5 mph becoming south in the afternoon.

    High: 68 °F

    Sunny

  • Friday Night

    Friday Night: Mostly clear, with a low around 51. South wind 5 to 10 mph.

    Low: 51 °F

    Mostly Clear

Detailed Forecast

Tonight
Mostly cloudy, with a low around 41. South wind around 5 mph becoming calm after midnight.
Tuesday
Cloudy, with a high near 61. Calm wind becoming south around 5 mph in the morning.
Tuesday Night
A chance of showers, with thunderstorms also possible after 3am. Patchy fog after 1am. Otherwise, cloudy, with a low around 55. South wind around 5 mph becoming calm. Chance of precipitation is 30%.
Wednesday
A 20 percent chance of showers and thunderstorms. Patchy fog before noon. Otherwise, cloudy, with a high near 68. Calm wind becoming southeast around 5 mph in the afternoon.
Wednesday Night
Mostly cloudy, with a low around 61. South wind 5 to 10 mph.
Thursday
Mostly sunny, with a high near 78. South southwest wind 5 to 15 mph becoming north in the afternoon. Winds could gust as high as 20 mph.
Thursday Night
Mostly clear, with a low around 44. North northeast wind 5 to 10 mph, with gusts as high as 20 mph.
Friday
Sunny, with a high near 68. North northeast wind around 5 mph becoming south in the afternoon.
Friday Night
Mostly clear, with a low around 51. South wind 5 to 10 mph.
Saturday
Mostly sunny, with a high near 76.
Saturday Night
Mostly clear, with a low around 57.
Sunday
Mostly sunny, with a high near 80.
Sunday Night
Partly cloudy, with a low around 56.
Monday
Mostly sunny, with a high near 78.
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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:
11:28 pm CST Dec 15, 2025
Forecast Valid:
11pm CST Dec 15, 2025-6pm CST Dec 22, 2025
 
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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