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

85°F

29°C

Humidity 65%
Wind Speed S 13 mph
Barometer 29.89 in (1011.3 mb)
Dewpoint 72°F (22°C)
Visibility 10.00 mi
Heat Index91°F (33°C)
Last update 3 Aug 10:56 pm CDT
Extended Forecast for

San Marcos TX

  • Tonight

    Tonight: Mostly clear, with a low around 75. South wind 5 to 10 mph.

    Low: 75 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 98. Heat index values as high as 105. South wind 5 to 10 mph.

    High: 98 °F

    Sunny

  • Tuesday Night

    Tuesday Night: 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, then gradually becoming sunny, with a high near 98. Heat index values as high as 104. South wind around 5 mph.

    High: 98 °F

    Decreasing
    Clouds

  • 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: Sunny, with a high near 97. South wind around 5 mph.

    High: 97 °F

    Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 76. South wind 5 to 10 mph.

    Low: 76 °F

    Mostly Clear

  • Friday

    Friday: Mostly sunny, with a high near 95. Calm wind becoming south around 5 mph in the morning.

    High: 95 °F

    Mostly Sunny

  • Friday Night

    Friday Night: A 20 percent chance of showers before 1am. Partly cloudy, with a low around 75. South southeast wind around 5 mph.

    Low: 75 °F

    Slight Chance
    Showers

Detailed Forecast

Tonight
Mostly clear, with a low around 75. South wind 5 to 10 mph.
Tuesday
Sunny, with a high near 98. Heat index values as high as 105. South wind 5 to 10 mph.
Tuesday Night
Increasing clouds, with a low around 76. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.
Wednesday
Mostly cloudy, then gradually becoming sunny, with a high near 98. Heat index values as high as 104. South wind around 5 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
Sunny, with a high near 97. South wind around 5 mph.
Thursday Night
Mostly clear, with a low around 76. South wind 5 to 10 mph.
Friday
Mostly sunny, with a high near 95. Calm wind becoming south around 5 mph in the morning.
Friday Night
A 20 percent chance of showers before 1am. Partly cloudy, with a low around 75. South southeast wind around 5 mph.
Saturday
Mostly sunny, with a high near 95.
Saturday Night
Mostly clear, with a low around 76.
Sunday
Mostly sunny, with a high near 95.
Sunday Night
Partly cloudy, with a low around 76.
Monday
Mostly sunny, with a high near 95.
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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:
11:32 pm CDT Aug 3, 2026
Forecast Valid:
11pm CDT Aug 3, 2026-6pm CDT Aug 10, 2026
 
Forecast Discussion
 
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Additional Resources

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National Digital Forecast Database

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation