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

89°F

32°C

Humidity 59%
Wind Speed Vrbl 7 mph
Barometer 30.05 in (1016.7 mb)
Dewpoint 73°F (23°C)
Visibility 10.00 mi
Heat Index97°F (36°C)
Last update 31 Aug 11:56 am CDT
Extended Forecast for

San Marcos Municipal Airport TX

  • This Afternoon

    This Afternoon: Sunny and hot, with a high near 100. Heat index values as high as 104. Southeast wind 5 to 10 mph.

    High: 100 °F

    Hot

  • Tonight

    Tonight: Mostly clear, with a low around 75. Southeast wind 5 to 10 mph becoming south southwest after midnight.

    Low: 75 °F

    Mostly Clear

  • Tuesday

    Tuesday: Mostly sunny and hot, with a high near 99. Heat index values as high as 106. Calm wind becoming southeast around 5 mph in the afternoon.

    High: 99 °F

    Hot

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 75. East wind 5 to 10 mph becoming south after midnight.

    Low: 75 °F

    Partly Cloudy

  • Wednesday

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

    High: 100 °F

    Hot

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 75. East southeast wind 10 to 15 mph becoming south after midnight.

    Low: 75 °F

    Partly Cloudy

  • Thursday

    Thursday: Mostly sunny and hot, with a high near 100. South wind around 10 mph.

    High: 100 °F

    Hot

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 75. South wind 10 to 15 mph, with gusts as high as 20 mph.

    Low: 75 °F

    Partly Cloudy

  • Friday

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

    High: 99 °F

    Hot

Detailed Forecast

This Afternoon
Sunny and hot, with a high near 100. Heat index values as high as 104. Southeast wind 5 to 10 mph.
Tonight
Mostly clear, with a low around 75. Southeast wind 5 to 10 mph becoming south southwest after midnight.
Tuesday
Mostly sunny and hot, with a high near 99. Heat index values as high as 106. Calm wind becoming southeast around 5 mph in the afternoon.
Tuesday Night
Partly cloudy, with a low around 75. East wind 5 to 10 mph becoming south after midnight.
Wednesday
Mostly sunny and hot, with a high near 100. South southwest wind around 5 mph.
Wednesday Night
Partly cloudy, with a low around 75. East southeast wind 10 to 15 mph becoming south after midnight.
Thursday
Mostly sunny and hot, with a high near 100. South wind around 10 mph.
Thursday Night
Partly cloudy, with a low around 75. South wind 10 to 15 mph, with gusts as high as 20 mph.
Friday
Mostly sunny and hot, with a high near 99. South wind 5 to 10 mph.
Friday Night
Mostly clear, with a low around 75.
Saturday
Mostly sunny and hot, with a high near 99.
Saturday Night
Mostly clear, with a low around 75.
Sunday
Mostly sunny and hot, with a high near 99.
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ABOUT THIS FORECAST

 
Point Forecast:
San Marcos Municipal Airport TX
 29.9°N 97.86°W (Elev. 600 ft)
Last Update:
12:42 pm CDT Aug 31, 2026
Forecast Valid:
12pm CDT Aug 31, 2026-6pm CDT Sep 6, 2026
 
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Additional Resources

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