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.

Mostly Cloudy

80°F

27°C

Humidity 60%
Wind Speed SE 12 mph
Barometer 29.91 in (1012.0 mb)
Dewpoint 65°F (18°C)
Visibility 10.00 mi
Heat Index82°F (28°C)
Last update 15 Apr 7:56 pm CDT
Extended Forecast for

San Marcos TX

  • Tonight

    Tonight: A 20 percent chance of showers and thunderstorms before 10pm. Increasing clouds, with a low around 68. South southeast wind 5 to 10 mph.

    Low: 68 °F

    Slight Chance
    T-storms then
    Mostly Cloudy

  • Thursday

    Thursday: Cloudy, then gradually becoming mostly sunny, with a high near 88. South wind 5 to 10 mph.

    High: 88 °F

    Decreasing
    Clouds

  • Thursday Night

    Thursday Night: Increasing clouds, with a low around 68. South southeast wind around 10 mph, with gusts as high as 20 mph.

    Low: 68 °F

    Increasing
    Clouds

  • Friday

    Friday: Cloudy, then gradually becoming mostly sunny, with a high near 89. South wind 10 to 15 mph, with gusts as high as 30 mph.

    High: 89 °F

    Decreasing
    Clouds

  • Friday Night

    Friday Night: Mostly cloudy, with a low around 67. South southeast wind 5 to 15 mph, with gusts as high as 25 mph.

    Low: 67 °F

    Mostly Cloudy

  • Saturday

    Saturday: A slight chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1pm. Mostly cloudy, with a high near 77. South wind 5 to 15 mph becoming north in the afternoon. Winds could gust as high as 25 mph. Chance of precipitation is 60%.

    High: 77 °F

    Slight Chance
    T-storms then
    Showers
    Likely

  • Saturday Night

    Saturday Night: A 50 percent chance of showers and thunderstorms. Cloudy, with a low around 54. North northeast wind around 15 mph, with gusts as high as 25 mph.

    Low: 54 °F

    Chance
    T-storms

  • Sunday

    Sunday: A 20 percent chance of showers. Mostly cloudy, with a high near 70. Northeast wind 10 to 15 mph, with gusts as high as 25 mph.

    High: 70 °F

    Slight Chance
    Showers

  • Sunday Night

    Sunday Night: A slight chance of showers, with thunderstorms also possible after 1am. Cloudy, with a low around 55. East northeast wind 5 to 10 mph. Chance of precipitation is 20%.

    Low: 55 °F

    Slight Chance
    Showers then
    Slight Chance
    T-storms

Detailed Forecast

Tonight
A 20 percent chance of showers and thunderstorms before 10pm. Increasing clouds, with a low around 68. South southeast wind 5 to 10 mph.
Thursday
Cloudy, then gradually becoming mostly sunny, with a high near 88. South wind 5 to 10 mph.
Thursday Night
Increasing clouds, with a low around 68. South southeast wind around 10 mph, with gusts as high as 20 mph.
Friday
Cloudy, then gradually becoming mostly sunny, with a high near 89. South wind 10 to 15 mph, with gusts as high as 30 mph.
Friday Night
Mostly cloudy, with a low around 67. South southeast wind 5 to 15 mph, with gusts as high as 25 mph.
Saturday
A slight chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1pm. Mostly cloudy, with a high near 77. South wind 5 to 15 mph becoming north in the afternoon. Winds could gust as high as 25 mph. Chance of precipitation is 60%.
Saturday Night
A 50 percent chance of showers and thunderstorms. Cloudy, with a low around 54. North northeast wind around 15 mph, with gusts as high as 25 mph.
Sunday
A 20 percent chance of showers. Mostly cloudy, with a high near 70. Northeast wind 10 to 15 mph, with gusts as high as 25 mph.
Sunday Night
A slight chance of showers, with thunderstorms also possible after 1am. Cloudy, with a low around 55. East northeast wind 5 to 10 mph. Chance of precipitation is 20%.
Monday
A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 65.
Monday Night
A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 57.
Tuesday
A 30 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 74.
Tuesday Night
Mostly cloudy, with a low around 63.
Wednesday
A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 81.
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ABOUT THIS FORECAST

 
Point Forecast:
San Marcos TX
 29.88°N 97.94°W (Elev. 577 ft)
Last Update:
6:44 pm CDT Apr 15, 2026
Forecast Valid:
8pm CDT Apr 15, 2026-6pm CDT Apr 22, 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