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.

Fair

77°F

25°C

Humidity 36%
Wind Speed S 9 mph
Barometer 30.05 in (1017.2 mb)
Dewpoint 48°F (9°C)
Visibility 10.00 mi
Heat Index78°F (26°C)
Last update 3 May 6:56 pm CDT
Extended Forecast for

San Marcos TX

  • Tonight

    Tonight: Partly cloudy, with a low around 57. South southeast wind around 5 mph.

    Low: 57 °F

    Partly Cloudy

  • Monday

    Monday: Sunny, with a high near 84. South wind 5 to 15 mph, with gusts as high as 25 mph.

    High: 84 °F

    Sunny

  • Monday Night

    Monday Night: Increasing clouds, with a low around 68. South wind 10 to 15 mph, with gusts as high as 20 mph.

    Low: 68 °F

    Increasing
    Clouds

  • Tuesday

    Tuesday: Mostly cloudy, with a high near 89. South wind around 10 mph, with gusts as high as 20 mph.

    High: 89 °F

    Mostly Cloudy

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 73. South southeast wind 5 to 10 mph.

    Low: 73 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 87. South wind around 5 mph.

    High: 87 °F

    Slight Chance
    T-storms

  • Wednesday Night

    Wednesday Night: A 30 percent chance of showers and thunderstorms after 1am. Mostly cloudy, with a low around 64. East northeast wind 5 to 10 mph.

    Low: 64 °F

    Mostly Cloudy
    then Chance
    T-storms

  • Thursday

    Thursday: A 30 percent chance of showers and thunderstorms. Cloudy, with a high near 71. North northeast wind around 15 mph, with gusts as high as 30 mph.

    High: 71 °F

    Chance
    T-storms

  • Thursday Night

    Thursday Night: A slight chance of showers and thunderstorms, then a chance of showers after 1am. Mostly cloudy, with a low around 60. Northeast wind 5 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 30%.

    Low: 60 °F

    Slight Chance
    T-storms then
    Chance
    Showers

Detailed Forecast

Tonight
Partly cloudy, with a low around 57. South southeast wind around 5 mph.
Monday
Sunny, with a high near 84. South wind 5 to 15 mph, with gusts as high as 25 mph.
Monday Night
Increasing clouds, with a low around 68. South wind 10 to 15 mph, with gusts as high as 20 mph.
Tuesday
Mostly cloudy, with a high near 89. South wind around 10 mph, with gusts as high as 20 mph.
Tuesday Night
Mostly cloudy, with a low around 73. South southeast wind 5 to 10 mph.
Wednesday
A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 87. South wind around 5 mph.
Wednesday Night
A 30 percent chance of showers and thunderstorms after 1am. Mostly cloudy, with a low around 64. East northeast wind 5 to 10 mph.
Thursday
A 30 percent chance of showers and thunderstorms. Cloudy, with a high near 71. North northeast wind around 15 mph, with gusts as high as 30 mph.
Thursday Night
A slight chance of showers and thunderstorms, then a chance of showers after 1am. Mostly cloudy, with a low around 60. Northeast wind 5 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 30%.
Friday
A 30 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 77.
Friday Night
A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 64.
Saturday
A 30 percent chance of showers and thunderstorms. Partly sunny, with a high near 81.
Saturday Night
A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 67.
Sunday
A 30 percent chance of showers and thunderstorms. Partly sunny, with a high near 87.
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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:
6:42 pm CDT May 3, 2026
Forecast Valid:
7pm CDT May 3, 2026-6pm CDT May 10, 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