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.

Overcast

72°F

22°C

Humidity 84%
Wind Speed S 15 G 23 mph
Barometer 29.92 in (1012.5 mb)
Dewpoint 67°F (19°C)
Visibility 10.00 mi
Last update 17 Apr 1:56 am CDT
Extended Forecast for

San Marcos TX

  • Overnight

    Overnight: Mostly cloudy, with a low around 69. South wind around 10 mph.

    Low: 69 °F

    Mostly Cloudy

  • 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 66. South southeast wind 10 to 15 mph, with gusts as high as 30 mph.

    Low: 66 °F

    Mostly Cloudy

  • Saturday

    Saturday: A 50 percent chance of showers and thunderstorms. Cloudy, with a high near 74. South wind 5 to 15 mph becoming north in the afternoon. Winds could gust as high as 30 mph.

    High: 74 °F

    Chance
    Showers then
    Chance
    T-storms

  • Saturday Night

    Saturday Night: Showers likely and possibly a thunderstorm before 1am, then a chance of showers and thunderstorms between 1am and 4am, then a chance of showers after 4am. Mostly cloudy, with a low around 53. North wind 15 to 20 mph, with gusts as high as 35 mph. Chance of precipitation is 60%.

    Low: 53 °F

    Showers
    Likely

  • Sunday

    Sunday: Partly sunny, with a high near 72. North northeast wind 10 to 15 mph, with gusts as high as 25 mph.

    High: 72 °F

    Partly Sunny

  • Sunday Night

    Sunday Night: Mostly cloudy, with a low around 55. East northeast wind 5 to 10 mph.

    Low: 55 °F

    Mostly Cloudy

  • Monday

    Monday: A chance of showers, with thunderstorms also possible after 1pm. Mostly cloudy, with a high near 66. East northeast wind around 5 mph. Chance of precipitation is 50%.

    High: 66 °F

    Chance
    Showers then
    Chance
    T-storms

  • Monday Night

    Monday Night: A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 57. East wind around 5 mph.

    Low: 57 °F

    Chance
    Showers then
    Chance
    T-storms

Detailed Forecast

Overnight
Mostly cloudy, with a low around 69. South wind around 10 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 66. South southeast wind 10 to 15 mph, with gusts as high as 30 mph.
Saturday
A 50 percent chance of showers and thunderstorms. Cloudy, with a high near 74. South wind 5 to 15 mph becoming north in the afternoon. Winds could gust as high as 30 mph.
Saturday Night
Showers likely and possibly a thunderstorm before 1am, then a chance of showers and thunderstorms between 1am and 4am, then a chance of showers after 4am. Mostly cloudy, with a low around 53. North wind 15 to 20 mph, with gusts as high as 35 mph. Chance of precipitation is 60%.
Sunday
Partly sunny, with a high near 72. North northeast wind 10 to 15 mph, with gusts as high as 25 mph.
Sunday Night
Mostly cloudy, with a low around 55. East northeast wind 5 to 10 mph.
Monday
A chance of showers, with thunderstorms also possible after 1pm. Mostly cloudy, with a high near 66. East northeast wind around 5 mph. Chance of precipitation is 50%.
Monday Night
A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 57. East wind around 5 mph.
Tuesday
A 40 percent chance of showers and thunderstorms. Cloudy, with a high near 74.
Tuesday Night
Mostly cloudy, with a low around 65.
Wednesday
A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 82.
Wednesday Night
A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 67.
Thursday
A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 84.
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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:
2:44 am CDT Apr 17, 2026
Forecast Valid:
2am CDT Apr 17, 2026-6pm CDT Apr 23, 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