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

74°F

23°C

Humidity 85%
Wind Speed E 7 mph
Barometer 29.94 in (1013.3 mb)
Dewpoint 69°F (21°C)
Visibility 10.00 mi
Last update 23 May 8:56 pm CDT
Extended Forecast for

San Marcos TX

  • Tonight

    Tonight: A 20 percent chance of showers and thunderstorms before 1am. Partly cloudy, with a low around 68. East wind around 5 mph becoming calm.

    Low: 68 °F

    Slight Chance
    T-storms

  • Sunday

    Sunday: A 20 percent chance of showers and thunderstorms after 1pm. Sunny, with a high near 84. Calm wind becoming east northeast around 5 mph in the afternoon.

    High: 84 °F

    Mostly Sunny
    then Slight
    Chance
    T-storms

  • Sunday Night

    Sunday Night: Increasing clouds, with a low around 68. East northeast wind around 5 mph becoming calm in the evening.

    Low: 68 °F

    Increasing
    Clouds

  • Memorial Day

    Memorial Day: Mostly cloudy, then gradually becoming sunny, with a high near 86. North wind around 5 mph becoming east northeast in the afternoon.

    High: 86 °F

    Decreasing
    Clouds

  • Monday Night

    Monday Night: Partly cloudy, with a low around 69. East wind around 5 mph becoming calm in the evening.

    Low: 69 °F

    Partly Cloudy

  • Tuesday

    Tuesday: A 30 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 86. Calm wind becoming southeast around 5 mph in the afternoon.

    High: 86 °F

    Mostly Sunny
    then Chance
    T-storms

  • Tuesday Night

    Tuesday Night: Showers and possibly a thunderstorm. Some of the storms could produce heavy rainfall. Low around 69. South southeast wind around 5 mph. Chance of precipitation is 80%.

    Low: 69 °F

    Heavy Rain

  • Wednesday

    Wednesday: Showers likely and possibly a thunderstorm. Mostly cloudy, with a high near 84. South southeast wind 5 to 10 mph. Chance of precipitation is 70%.

    High: 84 °F

    Showers
    Likely

  • Wednesday Night

    Wednesday Night: A 40 percent chance of showers and thunderstorms before 1am. Mostly cloudy, with a low around 70. Southeast wind around 5 mph becoming calm in the evening.

    Low: 70 °F

    Chance
    T-storms

Detailed Forecast

Tonight
A 20 percent chance of showers and thunderstorms before 1am. Partly cloudy, with a low around 68. East wind around 5 mph becoming calm.
Sunday
A 20 percent chance of showers and thunderstorms after 1pm. Sunny, with a high near 84. Calm wind becoming east northeast around 5 mph in the afternoon.
Sunday Night
Increasing clouds, with a low around 68. East northeast wind around 5 mph becoming calm in the evening.
Memorial Day
Mostly cloudy, then gradually becoming sunny, with a high near 86. North wind around 5 mph becoming east northeast in the afternoon.
Monday Night
Partly cloudy, with a low around 69. East wind around 5 mph becoming calm in the evening.
Tuesday
A 30 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 86. Calm wind becoming southeast around 5 mph in the afternoon.
Tuesday Night
Showers and possibly a thunderstorm. Some of the storms could produce heavy rainfall. Low around 69. South southeast wind around 5 mph. Chance of precipitation is 80%.
Wednesday
Showers likely and possibly a thunderstorm. Mostly cloudy, with a high near 84. South southeast wind 5 to 10 mph. Chance of precipitation is 70%.
Wednesday Night
A 40 percent chance of showers and thunderstorms before 1am. Mostly cloudy, with a low around 70. Southeast wind around 5 mph becoming calm in the evening.
Thursday
Partly sunny, with a high near 88.
Thursday Night
A 20 percent chance of showers and thunderstorms. Partly cloudy, with a low around 72.
Friday
Partly sunny, with a high near 91.
Friday Night
A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 73.
Saturday
A 20 percent chance of showers and thunderstorms. Partly sunny, with a high near 89.
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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:
9:00 pm CDT May 23, 2026
Forecast Valid:
9pm CDT May 23, 2026-6pm CDT May 30, 2026
 
Forecast Discussion
 
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Additional Resources

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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