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

93°F

34°C

Humidity 36%
Wind Speed SE 7 mph
Barometer 30.08 in
Dewpoint 62°F (17°C)
Visibility 10.00 mi
Heat Index94°F (34°C)
Last update 1 Aug 7:56 pm CDT
Extended Forecast for

San Marcos TX

  • Tonight

    Tonight: A 20 percent chance of showers and thunderstorms before 10pm. Partly cloudy, with a low around 76. South southeast wind around 5 mph becoming calm.

    Low: 76 °F

    Slight Chance
    T-storms then
    Partly Cloudy

  • Saturday

    Saturday: A 40 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 96. Heat index values as high as 102. Calm wind.

    High: 96 °F

    Mostly Sunny
    then Chance
    T-storms

  • Saturday Night

    Saturday Night: A chance of showers and thunderstorms before 10pm, then a slight chance of showers between 10pm and 1am. Partly cloudy, with a low around 76. North northwest wind around 5 mph becoming calm. Chance of precipitation is 30%.

    Low: 76 °F

    Chance
    T-storms then
    Slight Chance
    Showers

  • Sunday

    Sunday: A slight chance of showers between 1pm and 4pm, then a slight chance of showers and thunderstorms after 4pm. Sunny, with a high near 97. Heat index values as high as 105. Calm wind becoming east southeast around 5 mph. Chance of precipitation is 20%.

    High: 97 °F

    Sunny then
    Slight Chance
    T-storms

  • Sunday Night

    Sunday Night: A slight chance of showers and thunderstorms before 10pm, then a slight chance of showers between 10pm and 1am. Mostly clear, with a low around 76. South southeast wind around 5 mph. Chance of precipitation is 20%.

    Low: 76 °F

    Slight Chance
    T-storms then
    Slight Chance
    Showers

  • Monday

    Monday: A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 95. Calm wind becoming east southeast around 5 mph in the afternoon.

    High: 95 °F

    Mostly Sunny
    then Slight
    Chance
    T-storms

  • Monday Night

    Monday Night: Partly cloudy, with a low around 75. East southeast wind around 5 mph becoming calm after midnight.

    Low: 75 °F

    Partly Cloudy

  • Tuesday

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

    High: 94 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 75. East southeast wind around 5 mph becoming south after midnight.

    Low: 75 °F

    Mostly Clear

Detailed Forecast

Tonight
A 20 percent chance of showers and thunderstorms before 10pm. Partly cloudy, with a low around 76. South southeast wind around 5 mph becoming calm.
Saturday
A 40 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 96. Heat index values as high as 102. Calm wind.
Saturday Night
A chance of showers and thunderstorms before 10pm, then a slight chance of showers between 10pm and 1am. Partly cloudy, with a low around 76. North northwest wind around 5 mph becoming calm. Chance of precipitation is 30%.
Sunday
A slight chance of showers between 1pm and 4pm, then a slight chance of showers and thunderstorms after 4pm. Sunny, with a high near 97. Heat index values as high as 105. Calm wind becoming east southeast around 5 mph. Chance of precipitation is 20%.
Sunday Night
A slight chance of showers and thunderstorms before 10pm, then a slight chance of showers between 10pm and 1am. Mostly clear, with a low around 76. South southeast wind around 5 mph. Chance of precipitation is 20%.
Monday
A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 95. Calm wind becoming east southeast around 5 mph in the afternoon.
Monday Night
Partly cloudy, with a low around 75. East southeast wind around 5 mph becoming calm after midnight.
Tuesday
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 75. East southeast wind around 5 mph becoming south after midnight.
Wednesday
Sunny, with a high near 95.
Wednesday Night
Mostly clear, with a low around 75.
Thursday
Sunny, with a high near 96.
Thursday Night
Mostly clear, with a low around 75.
Friday
Sunny, with a high near 96.
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ABOUT THIS FORECAST

 
Point Forecast:
San Marcos TX
 29.88°N 97.94°W (Elev. 577 ft)
Last Update:
6:42 pm CDT Aug 1, 2025
Forecast Valid:
8pm CDT Aug 1, 2025-6pm CDT Aug 8, 2025
 
Forecast Discussion
 
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Additional Resources

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Hourly Weather Forecast

National Digital Forecast Database

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation