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

86°F

30°C

Humidity 63%
Wind Speed S 13 mph
Barometer 30.07 in (1017.2 mb)
Dewpoint 72°F (22°C)
Visibility 10.00 mi
Heat Index92°F (33°C)
Last update 17 Aug 10:56 pm CDT
Extended Forecast for

San Marcos TX

  • Tonight

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

    Low: 75 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny and hot, with a high near 100. Heat index values as high as 103. Southwest wind around 5 mph.

    High: 100 °F

    Hot

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 77. South wind 5 to 10 mph.

    Low: 77 °F

    Partly Cloudy

  • Wednesday

    Wednesday: Mostly sunny and hot, with a high near 100. South southwest wind 5 to 10 mph.

    High: 100 °F

    Hot

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 77. South wind 5 to 10 mph.

    Low: 77 °F

    Mostly Clear

  • Thursday

    Thursday: Mostly sunny and hot, with a high near 101. South southwest wind around 5 mph.

    High: 101 °F

    Hot

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 77. South southeast wind 5 to 10 mph.

    Low: 77 °F

    Mostly Clear

  • Friday

    Friday: Sunny and hot, with a high near 100. South southwest wind around 5 mph.

    High: 100 °F

    Hot

  • Friday Night

    Friday Night: Mostly clear, with a low around 77. South southeast wind around 5 mph.

    Low: 77 °F

    Mostly Clear

Detailed Forecast

Tonight
Mostly clear, with a low around 75. South southwest wind 5 to 10 mph.
Tuesday
Sunny and hot, with a high near 100. Heat index values as high as 103. Southwest wind around 5 mph.
Tuesday Night
Partly cloudy, with a low around 77. South wind 5 to 10 mph.
Wednesday
Mostly sunny and hot, with a high near 100. South southwest wind 5 to 10 mph.
Wednesday Night
Mostly clear, with a low around 77. South wind 5 to 10 mph.
Thursday
Mostly sunny and hot, with a high near 101. South southwest wind around 5 mph.
Thursday Night
Mostly clear, with a low around 77. South southeast wind 5 to 10 mph.
Friday
Sunny and hot, with a high near 100. South southwest wind around 5 mph.
Friday Night
Mostly clear, with a low around 77. South southeast wind around 5 mph.
Saturday
Sunny and hot, with a high near 101.
Saturday Night
Mostly clear, with a low around 78.
Sunday
Sunny and hot, with a high near 100.
Sunday Night
Mostly clear, with a low around 77.
Monday
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 97.94°W (Elev. 577 ft)
Last Update:
10:46 pm CDT Aug 17, 2026
Forecast Valid:
11pm CDT Aug 17, 2026-6pm CDT Aug 24, 2026
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation