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

97°F

36°C

Humidity 37%
Wind Speed S 8 mph
Barometer 29.94 in (1013.2 mb)
Dewpoint 67°F (19°C)
Visibility 10.00 mi
Heat Index101°F (38°C)
Last update 29 Aug 6:56 pm CDT
Extended Forecast for

San Marcos TX

  • Tonight

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

    Low: 75 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny, with a high near 98. Heat index values as high as 104. Calm wind becoming south around 5 mph in the afternoon.

    High: 98 °F

    Sunny

  • Sunday Night

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

    Low: 75 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 98. Heat index values as high as 104. Calm wind becoming south around 5 mph in the morning.

    High: 98 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 76. South southeast wind around 5 mph.

    Low: 76 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 97. Calm wind becoming south around 5 mph in the afternoon.

    High: 97 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 76. Southeast wind around 5 mph.

    Low: 76 °F

    Mostly Clear

  • Wednesday

    Wednesday: Sunny, with a high near 98. Calm wind becoming south around 5 mph in the afternoon.

    High: 98 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 76. Southeast wind around 5 mph.

    Low: 76 °F

    Mostly Clear

Detailed Forecast

Tonight
Mostly clear, with a low around 75. South wind around 5 mph.
Sunday
Sunny, with a high near 98. Heat index values as high as 104. Calm wind becoming south around 5 mph in the afternoon.
Sunday Night
Mostly clear, with a low around 75. South southeast wind 5 to 10 mph.
Monday
Sunny, with a high near 98. Heat index values as high as 104. Calm wind becoming south around 5 mph in the morning.
Monday Night
Mostly clear, with a low around 76. South southeast wind around 5 mph.
Tuesday
Sunny, with a high near 97. Calm wind becoming south around 5 mph in the afternoon.
Tuesday Night
Mostly clear, with a low around 76. Southeast wind around 5 mph.
Wednesday
Sunny, with a high near 98. Calm wind becoming south around 5 mph in the afternoon.
Wednesday Night
Mostly clear, with a low around 76. Southeast wind around 5 mph.
Thursday
Sunny and hot, with a high near 99.
Thursday Night
Mostly clear, with a low around 76.
Friday
Mostly sunny, with a high near 98.
Friday Night
Mostly clear, with a low around 77.
Saturday
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:
6:44 pm CDT Aug 29, 2026
Forecast Valid:
7pm CDT Aug 29, 2026-6pm CDT Sep 5, 2026
 
Forecast Discussion
 
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Additional Resources

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Hourly Weather Forecast

National Digital Forecast Database

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation