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

78°F

26°C

Humidity 87%
Wind Speed S 5 mph
Barometer 30.03 in (1016.1 mb)
Dewpoint 74°F (23°C)
Visibility 10.00 mi
Heat Index80°F (27°C)
Last update 10 Sep 7:56 am CDT
Extended Forecast for

San Marcos Municipal Airport TX

  • Today

    Today: Mostly sunny, with a high near 97. Heat index values as high as 104. Calm wind becoming south southeast around 5 mph in the afternoon.

    High: 97 °F

    Mostly Sunny

  • Tonight

    Tonight: Partly cloudy, with a low around 75. South southeast wind 5 to 10 mph.

    Low: 75 °F

    Partly Cloudy

  • Friday

    Friday: Mostly sunny, with a high near 98. Heat index values as high as 104. South wind 5 to 10 mph.

    High: 98 °F

    Mostly Sunny

  • Friday Night

    Friday Night: Partly cloudy, with a low around 75. South southeast wind 5 to 10 mph.

    Low: 75 °F

    Partly Cloudy

  • Saturday

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

    High: 100 °F

    Hot

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 75. South southeast wind 5 to 15 mph, with gusts as high as 20 mph.

    Low: 75 °F

    Mostly Clear

  • Sunday

    Sunday: Mostly sunny, with a high near 98. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.

    High: 98 °F

    Mostly Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 75. South wind 5 to 15 mph, with gusts as high as 20 mph.

    Low: 75 °F

    Partly Cloudy

  • Monday

    Monday: Mostly sunny and hot, with a high near 99. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.

    High: 99 °F

    Hot

Detailed Forecast

Today
Mostly sunny, with a high near 97. Heat index values as high as 104. Calm wind becoming south southeast around 5 mph in the afternoon.
Tonight
Partly cloudy, with a low around 75. South southeast wind 5 to 10 mph.
Friday
Mostly sunny, with a high near 98. Heat index values as high as 104. South wind 5 to 10 mph.
Friday Night
Partly cloudy, with a low around 75. South southeast wind 5 to 10 mph.
Saturday
Mostly sunny and hot, with a high near 100. South wind 5 to 10 mph.
Saturday Night
Mostly clear, with a low around 75. South southeast wind 5 to 15 mph, with gusts as high as 20 mph.
Sunday
Mostly sunny, with a high near 98. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.
Sunday Night
Partly cloudy, with a low around 75. South wind 5 to 15 mph, with gusts as high as 20 mph.
Monday
Mostly sunny and hot, with a high near 99. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.
Monday Night
Mostly clear, with a low around 75.
Tuesday
Mostly sunny and hot, with a high near 99.
Tuesday Night
Partly cloudy, with a low around 74.
Wednesday
Mostly sunny, with a high near 97.
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ABOUT THIS FORECAST

 
Point Forecast:
San Marcos Municipal Airport TX
 29.88°N 97.86°W (Elev. 600 ft)
Last Update:
6:42 am CDT Sep 10, 2026
Forecast Valid:
8am CDT Sep 10, 2026-6pm CDT Sep 16, 2026
 
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