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.

Partly Cloudy

88°F

31°C

Humidity 66%
Wind Speed S 14 G 23 mph
Barometer 29.95 in (1013.2 mb)
Dewpoint 75°F (24°C)
Visibility 10.00 mi
Heat Index98°F (37°C)
Last update 3 Sep 9:56 am CDT
Extended Forecast for

5 Miles SSW San Marcos TX

  • Today

    Today: A 20 percent chance of showers and thunderstorms after 4pm. Mostly sunny and hot, with a high near 99. Heat index values as high as 106. South southeast wind 5 to 10 mph.

    High: 99 °F

    Partly Sunny
    then Slight
    Chance
    T-storms

  • Tonight

    Tonight: A slight chance of showers and thunderstorms before 7pm, then a slight chance of showers after 4am. Partly cloudy, with a low around 77. South wind 5 to 15 mph, with gusts as high as 20 mph. Chance of precipitation is 20%.

    Low: 77 °F

    Slight Chance
    T-storms then
    Slight Chance
    Showers

  • Friday

    Friday: A 20 percent chance of showers and thunderstorms. Partly sunny, with a high near 95. Heat index values as high as 100. South wind around 5 mph.

    High: 95 °F

    Slight Chance
    T-storms

  • Friday Night

    Friday 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 73. East southeast wind 5 to 10 mph becoming light south after midnight. Chance of precipitation is 20%.

    Low: 73 °F

    Slight Chance
    T-storms then
    Slight Chance
    Showers

  • Saturday

    Saturday: A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 96. Calm wind becoming east southeast around 5 mph in the afternoon.

    High: 96 °F

    Mostly Sunny
    then Slight
    Chance
    T-storms

  • Saturday Night

    Saturday Night: Partly cloudy, with a low around 74. Southeast wind 5 to 10 mph becoming light south southeast in the evening.

    Low: 74 °F

    Partly Cloudy

  • Sunday

    Sunday: A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 96. Calm wind becoming southeast around 5 mph in the afternoon.

    High: 96 °F

    Mostly Sunny
    then Slight
    Chance
    T-storms

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 75. Southeast wind around 5 mph becoming calm in the evening.

    Low: 75 °F

    Mostly Clear

  • Labor Day

    Labor Day: A 20 percent chance of showers and thunderstorms after 1pm. Sunny, with a high near 96. Calm wind becoming south southeast around 5 mph in the afternoon.

    High: 96 °F

    Sunny then
    Slight Chance
    T-storms

Detailed Forecast

Today
A 20 percent chance of showers and thunderstorms after 4pm. Mostly sunny and hot, with a high near 99. Heat index values as high as 106. South southeast wind 5 to 10 mph.
Tonight
A slight chance of showers and thunderstorms before 7pm, then a slight chance of showers after 4am. Partly cloudy, with a low around 77. South wind 5 to 15 mph, with gusts as high as 20 mph. Chance of precipitation is 20%.
Friday
A 20 percent chance of showers and thunderstorms. Partly sunny, with a high near 95. Heat index values as high as 100. South wind around 5 mph.
Friday 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 73. East southeast wind 5 to 10 mph becoming light south after midnight. Chance of precipitation is 20%.
Saturday
A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 96. Calm wind becoming east southeast around 5 mph in the afternoon.
Saturday Night
Partly cloudy, with a low around 74. Southeast wind 5 to 10 mph becoming light south southeast in the evening.
Sunday
A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 96. Calm wind becoming southeast around 5 mph in the afternoon.
Sunday Night
Mostly clear, with a low around 75. Southeast wind around 5 mph becoming calm in the evening.
Labor Day
A 20 percent chance of showers and thunderstorms after 1pm. Sunny, with a high near 96. Calm wind becoming south southeast around 5 mph in the afternoon.
Monday Night
Mostly clear, with a low around 75.
Tuesday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 95.
Tuesday Night
Partly cloudy, with a low around 74.
Wednesday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 95.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
5 Miles SSW San Marcos TX
 29.81°N 97.96°W (Elev. 676 ft)
Last Update:
9:42 am CDT Sep 3, 2026
Forecast Valid:
10am CDT Sep 3, 2026-6pm CDT Sep 9, 2026
 
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