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.

A Few Clouds

98°F

37°C

Humidity 42%
Wind Speed S 10 mph
Barometer 29.94 in (1012.8 mb)
Dewpoint 71°F (22°C)
Visibility 10.00 mi
Heat Index106°F (41°C)
Last update 12 Aug 2:56 pm CDT
Extended Forecast for

San Marcos TX

  • This Afternoon

    This Afternoon: Sunny and hot, with a high near 100. Heat index values as high as 104. South wind around 10 mph, with gusts as high as 20 mph.

    High: 100 °F

    Hot

  • Tonight

    Tonight: Mostly clear, with a low around 76. South southeast wind 10 to 15 mph, with gusts as high as 25 mph.

    Low: 76 °F

    Mostly Clear

  • Thursday

    Thursday: Mostly sunny and hot, with a high near 100. Heat index values as high as 106. South wind 10 to 15 mph, with gusts as high as 20 mph.

    High: 100 °F

    Hot

  • Thursday Night

    Thursday Night: Increasing clouds, with a low around 77. South southeast wind 10 to 15 mph, with gusts as high as 30 mph.

    Low: 77 °F

    Increasing
    Clouds

  • Friday

    Friday: Mostly sunny, with a high near 98. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.

    High: 98 °F

    Mostly Sunny

  • Friday Night

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

    Low: 77 °F

    Partly Cloudy

  • Saturday

    Saturday: Mostly sunny and hot, with a high near 99. South southeast wind 5 to 10 mph.

    High: 99 °F

    Hot

  • Saturday Night

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

    Low: 74 °F

    Mostly Clear

  • Sunday

    Sunday: Mostly sunny and hot, with a high near 99. Calm wind becoming south around 5 mph in the afternoon.

    High: 99 °F

    Hot

Detailed Forecast

This Afternoon
Sunny and hot, with a high near 100. Heat index values as high as 104. South wind around 10 mph, with gusts as high as 20 mph.
Tonight
Mostly clear, with a low around 76. South southeast wind 10 to 15 mph, with gusts as high as 25 mph.
Thursday
Mostly sunny and hot, with a high near 100. Heat index values as high as 106. South wind 10 to 15 mph, with gusts as high as 20 mph.
Thursday Night
Increasing clouds, with a low around 77. South southeast wind 10 to 15 mph, with gusts as high as 30 mph.
Friday
Mostly sunny, with a high near 98. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.
Friday Night
Partly cloudy, with a low around 77. South wind 5 to 15 mph, with gusts as high as 20 mph.
Saturday
Mostly sunny and hot, with a high near 99. South southeast wind 5 to 10 mph.
Saturday Night
Mostly clear, with a low around 74. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.
Sunday
Mostly sunny and hot, with a high near 99. Calm wind becoming south around 5 mph in the afternoon.
Sunday Night
Mostly clear, with a low around 75.
Monday
Sunny and hot, with a high near 99.
Monday Night
Mostly clear, with a low around 76.
Tuesday
Sunny and hot, with a high near 100.
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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:
2:46 pm CDT Aug 12, 2026
Forecast Valid:
3pm CDT Aug 12, 2026-6pm CDT Aug 18, 2026
 
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