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

78°F

26°C

Humidity 74%
Wind Speed SE 9 mph
Barometer 30.19 in (1021.7 mb)
Dewpoint 69°F (21°C)
Visibility 10.00 mi
Heat Index80°F (27°C)
Last update 11 Apr 11:56 am CDT
Extended Forecast for

San Marcos Municipal Airport TX

  • This Afternoon

    This Afternoon: A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 80. Southeast wind 10 to 15 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: 80 °F

    Chance
    T-storms

  • Tonight

    Tonight: A 50 percent chance of showers and thunderstorms, mainly after 10pm. 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 quarter and half of an inch possible.

    High: 77 °F

    T-storms

  • Sunday Night

    Sunday Night: Showers and thunderstorms likely, mainly before 7pm. Cloudy, with a low around 68. South southeast wind around 10 mph, with gusts as high as 20 mph. Chance of precipitation is 60%.

    Low: 68 °F

    T-storms
    Likely

  • Monday

    Monday: A 20 percent chance of showers and thunderstorms after 1pm. Patchy fog before 9am. Otherwise, mostly cloudy, with a high near 84. South wind 5 to 15 mph, with gusts as high as 20 mph.

    High: 84 °F

    Patchy Fog
    then Slight
    Chance
    T-storms

  • Monday Night

    Monday 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

  • Tuesday

    Tuesday: A 20 percent chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 83. South wind 10 to 15 mph, with gusts as high as 25 mph.

    High: 83 °F

    Cloudy then
    Slight Chance
    T-storms

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 67. South southeast wind 10 to 15 mph, with gusts as high as 25 mph.

    Low: 67 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: A 20 percent chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 84. South wind 10 to 15 mph, with gusts as high as 25 mph.

    High: 84 °F

    Cloudy then
    Slight Chance
    T-storms

Detailed Forecast

This Afternoon
A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 80. Southeast wind 10 to 15 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, mainly after 10pm. 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 quarter and half of an inch possible.
Sunday Night
Showers and thunderstorms likely, mainly before 7pm. Cloudy, with a low around 68. South southeast wind around 10 mph, with gusts as high as 20 mph. Chance of precipitation is 60%.
Monday
A 20 percent chance of showers and thunderstorms after 1pm. Patchy fog before 9am. Otherwise, mostly cloudy, with a high near 84. South wind 5 to 15 mph, with gusts as high as 20 mph.
Monday Night
Mostly cloudy, with a low around 68. South southeast wind 10 to 15 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 83. South wind 10 to 15 mph, with gusts as high as 25 mph.
Tuesday Night
Mostly cloudy, with a low around 67. South southeast wind 10 to 15 mph, with gusts as high as 25 mph.
Wednesday
A 20 percent chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 84. South wind 10 to 15 mph, with gusts as high as 25 mph.
Wednesday Night
Mostly cloudy, with a low around 67.
Thursday
Partly sunny, with a high near 88.
Thursday Night
Partly cloudy, with a low around 67.
Friday
Partly sunny, with a high near 89.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
San Marcos Municipal Airport TX
 29.88°N 97.86°W (Elev. 600 ft)
Last Update:
12:22 pm CDT Apr 11, 2026
Forecast Valid:
12pm CDT Apr 11, 2026-6pm CDT Apr 17, 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