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

84°F

29°C

Humidity 70%
Wind Speed S 5 mph
Barometer 29.95 in (1013.3 mb)
Dewpoint 73°F (23°C)
Visibility 10.00 mi
Heat Index90°F (32°C)
Last update 3 Aug 11:56 pm CDT
Extended Forecast for

San Marcos TX

  • Overnight

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

    Low: 75 °F

    Mostly Clear

  • Monday

    Monday: A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 96. Heat index values as high as 105. Calm wind becoming east northeast around 5 mph in the afternoon.

    High: 96 °F

    Mostly Sunny
    then Slight
    Chance
    T-storms

  • Monday Night

    Monday Night: A slight chance of showers and thunderstorms before 10pm, then a slight chance of showers between 10pm and 1am. Partly cloudy, with a low around 74. East wind around 5 mph becoming calm after midnight. Chance of precipitation is 20%.

    Low: 74 °F

    Slight Chance
    T-storms then
    Slight Chance
    Showers

  • Tuesday

    Tuesday: Mostly sunny, with a high near 95. Heat index values as high as 102. Calm wind becoming east southeast around 5 mph in the afternoon.

    High: 95 °F

    Mostly Sunny

  • Tuesday Night

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

    Low: 74 °F

    Mostly Clear

  • Wednesday

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

    High: 96 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 74. South wind around 5 mph.

    Low: 74 °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

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 75. Southeast wind around 5 mph.

    Low: 75 °F

    Mostly Clear

Detailed Forecast

Overnight
Mostly clear, with a low around 75. South southwest wind around 5 mph.
Monday
A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 96. Heat index values as high as 105. Calm wind becoming east northeast around 5 mph in the afternoon.
Monday Night
A slight chance of showers and thunderstorms before 10pm, then a slight chance of showers between 10pm and 1am. Partly cloudy, with a low around 74. East wind around 5 mph becoming calm after midnight. Chance of precipitation is 20%.
Tuesday
Mostly sunny, with a high near 95. Heat index values as high as 102. Calm wind becoming east southeast around 5 mph in the afternoon.
Tuesday Night
Mostly clear, with a low around 74. East southeast wind around 5 mph becoming calm after midnight.
Wednesday
Sunny, with a high near 96. Calm wind becoming southeast around 5 mph in the afternoon.
Wednesday Night
Mostly clear, with a low around 74. 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. Southeast wind around 5 mph.
Friday
Sunny, with a high near 96.
Friday Night
Mostly clear, with a low around 75.
Saturday
Sunny, with a high near 96.
Saturday Night
Mostly clear, with a low around 74.
Sunday
Sunny, with a high near 95.
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ABOUT THIS FORECAST

 
Point Forecast:
San Marcos TX
 29.88°N 97.94°W (Elev. 577 ft)
Last Update:
11:32 pm CDT Aug 3, 2025
Forecast Valid:
12am CDT Aug 4, 2025-6pm CDT Aug 10, 2025
 
Forecast Discussion
 
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Additional Resources

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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