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.

Partly Cloudy

55°F

13°C

Humidity 90%
Wind Speed Calm
Barometer 30.11 in (1019.4 mb)
Dewpoint 52°F (11°C)
Visibility 10.00 mi
Last update 8 Apr 7:56 am CDT
Extended Forecast for

San Marcos TX

  • Today

    Today: Mostly sunny, with a high near 81. Calm wind becoming south southeast around 5 mph in the afternoon.

    High: 81 °F

    Mostly Sunny

  • Tonight

    Tonight: Increasing clouds, with a low around 60. Southeast wind around 5 mph becoming calm after midnight.

    Low: 60 °F

    Increasing
    Clouds

  • Thursday

    Thursday: A 30 percent chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 83. Light east wind becoming east southeast 5 to 10 mph in the morning.

    High: 83 °F

    Mostly Cloudy
    then Chance
    T-storms

  • Thursday Night

    Thursday Night: A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 64. Southeast wind 5 to 10 mph becoming light after midnight.

    Low: 64 °F

    Chance
    T-storms

  • Friday

    Friday: Showers and thunderstorms likely, mainly after 1pm. Mostly cloudy, with a high near 82. Light east southeast wind becoming southeast 5 to 10 mph in the morning. Winds could gust as high as 20 mph. Chance of precipitation is 60%.

    High: 82 °F

    Chance
    T-storms then
    T-storms
    Likely

  • Friday Night

    Friday Night: A 20 percent chance of showers and thunderstorms before 1am. Mostly cloudy, with a low around 65. Southeast wind 5 to 10 mph, with gusts as high as 20 mph.

    Low: 65 °F

    Slight Chance
    T-storms

  • Saturday

    Saturday: A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 82. Southeast wind 5 to 15 mph, with gusts as high as 25 mph.

    High: 82 °F

    Chance
    T-storms

  • Saturday Night

    Saturday Night: A 30 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 67. Southeast wind 10 to 15 mph, with gusts as high as 25 mph.

    Low: 67 °F

    Chance
    T-storms

  • Sunday

    Sunday: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1pm. Cloudy, with a high near 81. South wind 10 to 15 mph, with gusts as high as 25 mph. Chance of precipitation is 60%.

    High: 81 °F

    Chance
    T-storms then
    Showers
    Likely

Detailed Forecast

Today
Mostly sunny, with a high near 81. Calm wind becoming south southeast around 5 mph in the afternoon.
Tonight
Increasing clouds, with a low around 60. Southeast wind around 5 mph becoming calm after midnight.
Thursday
A 30 percent chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 83. Light east wind becoming east southeast 5 to 10 mph in the morning.
Thursday Night
A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 64. Southeast wind 5 to 10 mph becoming light after midnight.
Friday
Showers and thunderstorms likely, mainly after 1pm. Mostly cloudy, with a high near 82. Light east southeast wind becoming southeast 5 to 10 mph in the morning. Winds could gust as high as 20 mph. Chance of precipitation is 60%.
Friday Night
A 20 percent chance of showers and thunderstorms before 1am. Mostly cloudy, with a low around 65. Southeast wind 5 to 10 mph, with gusts as high as 20 mph.
Saturday
A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 82. Southeast wind 5 to 15 mph, with gusts as high as 25 mph.
Saturday Night
A 30 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 67. Southeast wind 10 to 15 mph, with gusts as high as 25 mph.
Sunday
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1pm. Cloudy, with a high near 81. South wind 10 to 15 mph, with gusts as high as 25 mph. Chance of precipitation is 60%.
Sunday Night
A 20 percent chance of showers and thunderstorms before 1am. Mostly cloudy, with a low around 67.
Monday
A 30 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 85.
Monday Night
Mostly cloudy, with a low around 68.
Tuesday
A 30 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 86.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
San Marcos TX
 29.88°N 97.91°W (Elev. 597 ft)
Last Update:
6:42 am CDT Apr 8, 2026
Forecast Valid:
7am CDT Apr 8, 2026-6pm CDT Apr 14, 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