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

63°F

17°C

Humidity 97%
Wind Speed E 8 mph
Barometer 30.10 in (1018.9 mb)
Dewpoint 62°F (17°C)
Visibility 10.00 mi
Last update 21 Apr 6:56 pm CDT
Extended Forecast for

San Marcos Municipal Airport TX

  • Tonight

    Tonight: A 20 percent chance of showers. Patchy fog after 8pm. Otherwise, cloudy, with a low around 65. Southeast wind 5 to 10 mph.

    Low: 65 °F

    Slight Chance
    Showers and
    Patchy Fog

  • Wednesday

    Wednesday: A chance of showers, with thunderstorms also possible after 1pm. Areas of fog before 11am. Otherwise, mostly cloudy, with a high near 80. South southeast wind 5 to 10 mph. Chance of precipitation is 40%.

    High: 80 °F

    Chance
    Showers and
    Areas Fog
    then Chance
    T-storms

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 66. South wind 5 to 10 mph.

    Low: 66 °F

    Mostly Cloudy

  • Thursday

    Thursday: Mostly cloudy, with a high near 83. South wind 5 to 15 mph, with gusts as high as 20 mph.

    High: 83 °F

    Mostly Cloudy

  • Thursday Night

    Thursday 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

  • Friday

    Friday: A 20 percent chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 86. South southwest wind 5 to 10 mph.

    High: 86 °F

    Mostly Cloudy
    then Slight
    Chance
    T-storms

  • Friday Night

    Friday Night: Partly cloudy, with a low around 67. South wind around 5 mph.

    Low: 67 °F

    Partly Cloudy

  • Saturday

    Saturday: Mostly cloudy, with a high near 89. South wind 5 to 10 mph.

    High: 89 °F

    Mostly Cloudy

  • Saturday Night

    Saturday Night: Mostly cloudy, with a low around 69. South southeast wind around 5 mph.

    Low: 69 °F

    Mostly Cloudy

Detailed Forecast

Tonight
A 20 percent chance of showers. Patchy fog after 8pm. Otherwise, cloudy, with a low around 65. Southeast wind 5 to 10 mph.
Wednesday
A chance of showers, with thunderstorms also possible after 1pm. Areas of fog before 11am. Otherwise, mostly cloudy, with a high near 80. South southeast wind 5 to 10 mph. Chance of precipitation is 40%.
Wednesday Night
Mostly cloudy, with a low around 66. South wind 5 to 10 mph.
Thursday
Mostly cloudy, with a high near 83. South wind 5 to 15 mph, with gusts as high as 20 mph.
Thursday Night
Mostly cloudy, with a low around 68. South southeast wind around 10 mph, with gusts as high as 20 mph.
Friday
A 20 percent chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 86. South southwest wind 5 to 10 mph.
Friday Night
Partly cloudy, with a low around 67. South wind around 5 mph.
Saturday
Mostly cloudy, with a high near 89. South wind 5 to 10 mph.
Saturday Night
Mostly cloudy, with a low around 69. South southeast wind around 5 mph.
Sunday
Mostly cloudy, with a high near 91.
Sunday Night
Mostly cloudy, with a low around 70.
Monday
Partly sunny, with a high near 93.
Monday Night
Partly cloudy, with a low around 66.
Tuesday
Partly sunny, with a high near 92.
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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:
6:56 pm CDT Apr 21, 2026
Forecast Valid:
7pm CDT Apr 21, 2026-6pm CDT Apr 28, 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