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.

A Few Clouds

83°F

28°C

Humidity 63%
Wind Speed S 8 mph
Barometer 29.90 in
Dewpoint 69°F (21°C)
Visibility 10.00 mi
Heat Index87°F (31°C)
Last update 22 Apr 5:56 pm CDT
Extended Forecast for

San Marcos TX

  • Tonight

    Tonight: A 30 percent chance of showers and thunderstorms before 7pm. Mostly cloudy, with a low around 67. South wind 5 to 10 mph.

    Low: 67 °F

    Chance
    T-storms then
    Mostly Cloudy

  • Thursday

    Thursday: Mostly cloudy, with a high near 82. South wind 5 to 10 mph, with gusts as high as 20 mph.

    High: 82 °F

    Mostly Cloudy

  • Thursday Night

    Thursday Night: Mostly cloudy, with a low around 69. South southeast wind around 10 mph, with gusts as high as 20 mph.

    Low: 69 °F

    Mostly Cloudy

  • Friday

    Friday: A 20 percent chance of showers and thunderstorms after 1pm. Cloudy, then gradually becoming mostly sunny, with a high near 85. South wind 5 to 10 mph.

    High: 85 °F

    Cloudy then
    Slight Chance
    T-storms

  • Friday Night

    Friday Night: Mostly cloudy, with a low around 70. South wind around 5 mph.

    Low: 70 °F

    Mostly Cloudy

  • Saturday

    Saturday: Mostly cloudy, with a high near 89. South wind around 5 mph.

    High: 89 °F

    Mostly Cloudy

  • Saturday Night

    Saturday Night: Partly cloudy, with a low around 70. South southeast wind around 5 mph.

    Low: 70 °F

    Partly Cloudy

  • Sunday

    Sunday: Mostly cloudy, with a high near 90. South wind 5 to 10 mph, with gusts as high as 20 mph.

    High: 90 °F

    Mostly Cloudy

  • Sunday Night

    Sunday Night: Mostly cloudy, with a low around 71. South wind around 10 mph, with gusts as high as 20 mph.

    Low: 71 °F

    Mostly Cloudy

Detailed Forecast

Tonight
A 30 percent chance of showers and thunderstorms before 7pm. Mostly cloudy, with a low around 67. South wind 5 to 10 mph.
Thursday
Mostly cloudy, with a high near 82. South wind 5 to 10 mph, with gusts as high as 20 mph.
Thursday Night
Mostly cloudy, with a low around 69. South southeast wind around 10 mph, with gusts as high as 20 mph.
Friday
A 20 percent chance of showers and thunderstorms after 1pm. Cloudy, then gradually becoming mostly sunny, with a high near 85. South wind 5 to 10 mph.
Friday Night
Mostly cloudy, with a low around 70. South wind around 5 mph.
Saturday
Mostly cloudy, with a high near 89. South wind around 5 mph.
Saturday Night
Partly cloudy, with a low around 70. South southeast wind around 5 mph.
Sunday
Mostly cloudy, with a high near 90. South wind 5 to 10 mph, with gusts as high as 20 mph.
Sunday Night
Mostly cloudy, with a low around 71. South wind around 10 mph, with gusts as high as 20 mph.
Monday
Mostly cloudy, with a high near 92.
Monday Night
Partly cloudy, with a low around 69.
Tuesday
Partly sunny, with a high near 92.
Tuesday Night
Mostly cloudy, with a low around 69.
Wednesday
Mostly cloudy, with a high near 92.
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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:
5:32 pm CDT Apr 22, 2026
Forecast Valid:
6pm CDT Apr 22, 2026-6pm CDT Apr 29, 2026
 
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