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

71°F

22°C

Humidity 96%
Wind Speed NW 5 mph
Barometer 30.03 in (1016.2 mb)
Dewpoint 70°F (21°C)
Visibility 10.00 mi
Last update 3 Aug 6:56 am CDT
Extended Forecast for

San Marcos TX

  • Today

    Today: Sunny, with a high near 97. Heat index values as high as 104. Calm wind.

    High: 97 °F

    Sunny

  • Tonight

    Tonight: Mostly clear, with a low around 76. South wind around 5 mph becoming calm after midnight.

    Low: 76 °F

    Mostly Clear

  • Monday

    Monday: A 30 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 96. Heat index values as high as 101. Calm wind becoming east around 5 mph in the afternoon.

    High: 96 °F

    Mostly Sunny
    then Chance
    T-storms

  • Monday Night

    Monday Night: A 20 percent chance of showers before 1am. Partly cloudy, with a low around 75. East wind around 5 mph becoming calm after midnight.

    Low: 75 °F

    Slight Chance
    Showers

  • Tuesday

    Tuesday: Mostly sunny, with a high near 94. Calm wind becoming east southeast around 5 mph in the afternoon.

    High: 94 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 74. East wind around 5 mph becoming calm after midnight.

    Low: 74 °F

    Mostly Clear

  • Wednesday

    Wednesday: Sunny, with a high near 95. Calm wind becoming southeast around 5 mph in the afternoon.

    High: 95 °F

    Sunny

  • Wednesday Night

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

    Low: 75 °F

    Mostly Clear

  • Thursday

    Thursday: Sunny, with a high near 96. Calm wind becoming south around 5 mph in the afternoon.

    High: 96 °F

    Sunny

Detailed Forecast

Today
Sunny, with a high near 97. Heat index values as high as 104. Calm wind.
Tonight
Mostly clear, with a low around 76. South wind around 5 mph becoming calm after midnight.
Monday
A 30 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 96. Heat index values as high as 101. Calm wind becoming east around 5 mph in the afternoon.
Monday Night
A 20 percent chance of showers before 1am. Partly cloudy, with a low around 75. East wind around 5 mph becoming calm after midnight.
Tuesday
Mostly sunny, with a high near 94. Calm wind becoming east southeast around 5 mph in the afternoon.
Tuesday Night
Mostly clear, with a low around 74. East wind around 5 mph becoming calm after midnight.
Wednesday
Sunny, with a high near 95. Calm wind becoming southeast around 5 mph in the afternoon.
Wednesday Night
Mostly clear, with a low around 75. South wind around 5 mph.
Thursday
Sunny, with a high near 96. Calm wind becoming south around 5 mph in the afternoon.
Thursday Night
Mostly clear, with a low around 75.
Friday
Sunny, with a high near 96.
Friday Night
Mostly clear, with a low around 75.
Saturday
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:
6:44 am CDT Aug 3, 2025
Forecast Valid:
7am CDT Aug 3, 2025-6pm CDT Aug 9, 2025
 
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