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

92°F

33°C

Humidity 56%
Wind Speed S 8 mph
Barometer 29.93 in (1012.6 mb)
Dewpoint 74°F (23°C)
Visibility 10.00 mi
Heat Index102°F (39°C)
Last update 28 Jul 12:56 pm CDT
Extended Forecast for

San Marcos TX

  • This Afternoon

    This Afternoon: Sunny, with a high near 97. Heat index values as high as 104. South wind around 10 mph.

    High: 97 °F

    Sunny

  • Tonight

    Tonight: Increasing clouds, with a low around 76. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.

    Low: 76 °F

    Increasing
    Clouds

  • Wednesday

    Wednesday: Mostly cloudy through mid morning, then gradual clearing, with a high near 97. Heat index values as high as 105. South wind 5 to 10 mph.

    High: 97 °F

    Becoming
    Sunny

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 76. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.

    Low: 76 °F

    Mostly Clear

  • Thursday

    Thursday: Mostly sunny and hot, with a high near 99. South southwest wind around 5 mph.

    High: 99 °F

    Hot

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 75. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.

    Low: 75 °F

    Partly Cloudy

  • Friday

    Friday: Sunny and hot, with a high near 99. South southwest wind around 5 mph.

    High: 99 °F

    Hot

  • Friday Night

    Friday Night: Mostly clear, with a low around 78. South wind 5 to 10 mph.

    Low: 78 °F

    Mostly Clear

  • Saturday

    Saturday: Mostly sunny and hot, with a high near 101. Southwest wind around 5 mph.

    High: 101 °F

    Hot

Detailed Forecast

This Afternoon
Sunny, with a high near 97. Heat index values as high as 104. South wind around 10 mph.
Tonight
Increasing clouds, with a low around 76. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.
Wednesday
Mostly cloudy through mid morning, then gradual clearing, with a high near 97. Heat index values as high as 105. South wind 5 to 10 mph.
Wednesday Night
Mostly clear, with a low around 76. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.
Thursday
Mostly sunny and hot, with a high near 99. South southwest wind around 5 mph.
Thursday Night
Partly cloudy, with a low around 75. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.
Friday
Sunny and hot, with a high near 99. South southwest wind around 5 mph.
Friday Night
Mostly clear, with a low around 78. South wind 5 to 10 mph.
Saturday
Mostly sunny and hot, with a high near 101. Southwest wind around 5 mph.
Saturday Night
Partly cloudy, with a low around 79.
Sunday
Mostly sunny, with a high near 98.
Sunday Night
Mostly clear, with a low around 77.
Monday
Mostly sunny, with a high near 98.
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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:
12:44 pm CDT Jul 28, 2026
Forecast Valid:
1pm CDT Jul 28, 2026-6pm CDT Aug 3, 2026
 
Forecast Discussion
 
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Additional Resources

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Chance of Precipitation