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

79°F

26°C

Humidity 67%
Wind Speed S 13 mph
Barometer 30.08 in (1017.9 mb)
Dewpoint 67°F (19°C)
Visibility 10.00 mi
Heat Index81°F (27°C)
Last update 11 Apr 3:56 pm CDT
Extended Forecast for

San Marcos TX

  • This Afternoon

    This Afternoon: A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 79. Southeast wind around 10 mph, with gusts as high as 20 mph. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    High: 79 °F

    Chance
    T-storms

  • Tonight

    Tonight: A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 68. Southeast wind around 10 mph, with gusts as high as 20 mph. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    Low: 68 °F

    Chance
    T-storms

  • Sunday

    Sunday: Showers and thunderstorms. High near 77. South southeast wind 10 to 15 mph, with gusts as high as 25 mph. Chance of precipitation is 80%. New rainfall amounts between a half and three quarters of an inch possible.

    High: 77 °F

    T-storms

  • Sunday Night

    Sunday Night: A 50 percent chance of showers and thunderstorms, mainly before 1am. Cloudy, with a low around 69. South wind around 10 mph, with gusts as high as 20 mph.

    Low: 69 °F

    Chance
    T-storms

  • Monday

    Monday: A 20 percent chance of showers and thunderstorms after 1pm. Patchy fog before 9am. Otherwise, mostly cloudy, with a high near 83. South wind 5 to 10 mph, with gusts as high as 20 mph.

    High: 83 °F

    Patchy Fog
    then Slight
    Chance
    T-storms

  • Monday Night

    Monday Night: Mostly cloudy, with a low around 68. South southeast wind around 10 mph, with gusts as high as 20 mph.

    Low: 68 °F

    Mostly Cloudy

  • Tuesday

    Tuesday: A 20 percent chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 82. South wind 10 to 15 mph, with gusts as high as 25 mph.

    High: 82 °F

    Cloudy then
    Slight Chance
    T-storms

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 68. South southeast wind 10 to 15 mph, with gusts as high as 20 mph.

    Low: 68 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: A 30 percent chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 84. South wind around 10 mph, with gusts as high as 20 mph.

    High: 84 °F

    Cloudy then
    Chance
    T-storms

Detailed Forecast

This Afternoon
A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 79. Southeast wind around 10 mph, with gusts as high as 20 mph. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Tonight
A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 68. Southeast wind around 10 mph, with gusts as high as 20 mph. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Sunday
Showers and thunderstorms. High near 77. South southeast wind 10 to 15 mph, with gusts as high as 25 mph. Chance of precipitation is 80%. New rainfall amounts between a half and three quarters of an inch possible.
Sunday Night
A 50 percent chance of showers and thunderstorms, mainly before 1am. Cloudy, with a low around 69. South wind around 10 mph, with gusts as high as 20 mph.
Monday
A 20 percent chance of showers and thunderstorms after 1pm. Patchy fog before 9am. Otherwise, mostly cloudy, with a high near 83. South wind 5 to 10 mph, with gusts as high as 20 mph.
Monday Night
Mostly cloudy, with a low around 68. South southeast wind around 10 mph, with gusts as high as 20 mph.
Tuesday
A 20 percent chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 82. South wind 10 to 15 mph, with gusts as high as 25 mph.
Tuesday Night
Mostly cloudy, with a low around 68. South southeast wind 10 to 15 mph, with gusts as high as 20 mph.
Wednesday
A 30 percent chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 84. South wind around 10 mph, with gusts as high as 20 mph.
Wednesday Night
A 20 percent chance of showers and thunderstorms before 1am. Mostly cloudy, with a low around 68.
Thursday
Partly sunny, with a high near 88.
Thursday Night
Mostly cloudy, with a low around 68.
Friday
Mostly cloudy, with a high near 88.
Friday Night
Mostly cloudy, with a low around 69.
Saturday
A chance of showers and thunderstorms. Mostly cloudy, with a high near 85.
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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:
2:46 pm CDT Apr 11, 2026
Forecast Valid:
4pm CDT Apr 11, 2026-6pm CDT Apr 18, 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