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 and Breezy

96°F

36°C

Humidity 44%
Wind Speed S 21 G 26 mph
Barometer 29.90 in (1011.4 mb)
Dewpoint 71°F (22°C)
Visibility 10.00 mi
Heat Index103°F (39°C)
Last update 13 Aug 6:56 pm CDT
Extended Forecast for

San Marcos TX

  • Tonight

    Tonight: Increasing clouds, with a low around 77. South southeast wind 10 to 15 mph, with gusts as high as 25 mph.

    Low: 77 °F

    Increasing
    Clouds

  • Friday

    Friday: Mostly cloudy, then gradually becoming sunny, with a high near 97. Heat index values as high as 105. South wind 5 to 10 mph, with gusts as high as 20 mph.

    High: 97 °F

    Decreasing
    Clouds

  • Friday Night

    Friday Night: Increasing clouds, with a low around 77. South wind 5 to 15 mph, with gusts as high as 20 mph.

    Low: 77 °F

    Increasing
    Clouds

  • Saturday

    Saturday: Mostly sunny, with a high near 98. Heat index values as high as 104. South wind 5 to 10 mph.

    High: 98 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: Partly cloudy, with a low around 74. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.

    Low: 74 °F

    Partly Cloudy

  • Sunday

    Sunday: Mostly sunny, with a high near 98. Calm wind becoming south around 5 mph in the afternoon.

    High: 98 °F

    Mostly Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 74. South southeast wind 5 to 10 mph.

    Low: 74 °F

    Mostly Clear

  • Monday

    Monday: Sunny and hot, with a high near 99. Calm wind becoming south southeast around 5 mph in the afternoon.

    High: 99 °F

    Hot

  • Monday Night

    Monday Night: Clear, with a low around 75. South southeast wind around 5 mph.

    Low: 75 °F

    Clear

Detailed Forecast

Tonight
Increasing clouds, with a low around 77. South southeast wind 10 to 15 mph, with gusts as high as 25 mph.
Friday
Mostly cloudy, then gradually becoming sunny, with a high near 97. Heat index values as high as 105. South wind 5 to 10 mph, with gusts as high as 20 mph.
Friday Night
Increasing clouds, with a low around 77. South wind 5 to 15 mph, with gusts as high as 20 mph.
Saturday
Mostly sunny, with a high near 98. Heat index values as high as 104. South wind 5 to 10 mph.
Saturday Night
Partly cloudy, with a low around 74. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.
Sunday
Mostly sunny, with a high near 98. Calm wind becoming south around 5 mph in the afternoon.
Sunday Night
Mostly clear, with a low around 74. South southeast wind 5 to 10 mph.
Monday
Sunny and hot, with a high near 99. Calm wind becoming south southeast around 5 mph in the afternoon.
Monday Night
Clear, with a low around 75. South southeast wind around 5 mph.
Tuesday
Sunny and hot, with a high near 99.
Tuesday Night
Mostly clear, with a low around 77.
Wednesday
Sunny and hot, with a high near 99.
Wednesday Night
Mostly clear, with a low around 75.
Thursday
Sunny and hot, with a high near 99.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
San Marcos TX
 29.88°N 97.94°W (Elev. 577 ft)
Last Update:
7:44 pm CDT Aug 13, 2026
Forecast Valid:
7pm CDT Aug 13, 2026-6pm CDT Aug 20, 2026
 
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