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.

Mostly Cloudy

81°F

27°C

Humidity 67%
Wind Speed S 14 mph
Barometer 29.96 in (1013.5 mb)
Dewpoint 69°F (21°C)
Visibility 10.00 mi
Heat Index84°F (29°C)
Last update 15 May 10:56 am CDT
Extended Forecast for

San Marcos TX

  • Today

    Today: Partly sunny, with a high near 91. South wind around 15 mph, with gusts as high as 25 mph.

    High: 91 °F

    Partly Sunny

  • Tonight

    Tonight: Mostly cloudy, with a low around 70. South southeast wind 10 to 15 mph, with gusts as high as 25 mph.

    Low: 70 °F

    Mostly Cloudy

  • Saturday

    Saturday: Partly sunny, with a high near 90. South wind 10 to 15 mph, with gusts as high as 25 mph.

    High: 90 °F

    Partly Sunny

  • Saturday Night

    Saturday Night: Mostly cloudy, with a low around 75. South southeast wind 10 to 15 mph, with gusts as high as 30 mph.

    Low: 75 °F

    Mostly Cloudy

  • Sunday

    Sunday: Mostly cloudy, with a high near 90. South southeast wind 10 to 15 mph, with gusts as high as 30 mph.

    High: 90 °F

    Mostly Cloudy

  • Sunday Night

    Sunday Night: Mostly cloudy, with a low around 78. South southeast wind around 15 mph, with gusts as high as 30 mph.

    Low: 78 °F

    Mostly Cloudy

  • Monday

    Monday: A 40 percent chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 91. South southeast wind 15 to 20 mph, with gusts as high as 30 mph.

    High: 91 °F

    Mostly Cloudy
    then Chance
    T-storms

  • Monday Night

    Monday Night: A 40 percent chance of showers and thunderstorms, mainly before 1am. Mostly cloudy, with a low around 78. South southeast wind around 15 mph, with gusts as high as 30 mph.

    Low: 78 °F

    Chance
    T-storms

  • Tuesday

    Tuesday: A 40 percent chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 90. South southeast wind 10 to 15 mph, with gusts as high as 20 mph.

    High: 90 °F

    Cloudy then
    Chance
    T-storms

Detailed Forecast

Today
Partly sunny, with a high near 91. South wind around 15 mph, with gusts as high as 25 mph.
Tonight
Mostly cloudy, with a low around 70. South southeast wind 10 to 15 mph, with gusts as high as 25 mph.
Saturday
Partly sunny, with a high near 90. South wind 10 to 15 mph, with gusts as high as 25 mph.
Saturday Night
Mostly cloudy, with a low around 75. South southeast wind 10 to 15 mph, with gusts as high as 30 mph.
Sunday
Mostly cloudy, with a high near 90. South southeast wind 10 to 15 mph, with gusts as high as 30 mph.
Sunday Night
Mostly cloudy, with a low around 78. South southeast wind around 15 mph, with gusts as high as 30 mph.
Monday
A 40 percent chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 91. South southeast wind 15 to 20 mph, with gusts as high as 30 mph.
Monday Night
A 40 percent chance of showers and thunderstorms, mainly before 1am. Mostly cloudy, with a low around 78. South southeast wind around 15 mph, with gusts as high as 30 mph.
Tuesday
A 40 percent chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 90. South southeast wind 10 to 15 mph, with gusts as high as 20 mph.
Tuesday Night
Showers likely and possibly a thunderstorm before 1am, then a chance of showers and thunderstorms after 1am. Mostly cloudy, with a low around 75. Chance of precipitation is 60%.
Wednesday
Showers and thunderstorms likely. Mostly cloudy, with a high near 85. Chance of precipitation is 60%.
Wednesday Night
A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 72.
Thursday
Showers and thunderstorms likely. Mostly cloudy, with a high near 82. Chance of precipitation is 60%.
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ABOUT THIS FORECAST

 
Point Forecast:
San Marcos TX
 29.88°N 97.94°W (Elev. 577 ft)
Last Update:
6:42 am CDT May 15, 2026
Forecast Valid:
11am CDT May 15, 2026-6pm CDT May 21, 2026
 
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Additional Resources

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation