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 with Haze

83°F

28°C

Humidity 74%
Wind Speed SE 14 mph
Barometer 29.85 in (1010.1 mb)
Dewpoint 74°F (23°C)
Visibility 5.00 mi
Heat Index90°F (32°C)
Last update 27 Apr 1:56 pm CDT
Extended Forecast for

San Marcos TX

  • This Afternoon

    This Afternoon: Mostly sunny, with a high near 93. Heat index values as high as 101. South wind 5 to 10 mph.

    High: 93 °F

    Mostly Sunny

  • Tonight

    Tonight: Increasing clouds, with a low around 74. South southeast wind 5 to 10 mph.

    Low: 74 °F

    Increasing
    Clouds

  • Tuesday

    Tuesday: Cloudy, then gradually becoming mostly sunny, with a high near 94. Heat index values as high as 102. South wind 5 to 15 mph, with gusts as high as 25 mph.

    High: 94 °F

    Decreasing
    Clouds

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 72. South southeast wind 5 to 10 mph.

    Low: 72 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: A 30 percent chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 89. South wind around 5 mph becoming northeast in the afternoon.

    High: 89 °F

    Mostly Cloudy
    then Chance
    T-storms

  • Wednesday Night

    Wednesday Night: A 30 percent chance of showers and thunderstorms, mainly before 1am. Mostly cloudy, with a low around 67. Northeast wind 5 to 10 mph.

    Low: 67 °F

    Chance
    T-storms then
    Chance
    Showers

  • Thursday

    Thursday: A 40 percent chance of showers and thunderstorms. Cloudy, with a high near 82. East wind 5 to 10 mph, with gusts as high as 20 mph.

    High: 82 °F

    Chance
    Showers then
    Chance
    T-storms

  • Thursday Night

    Thursday Night: A 50 percent chance of showers and thunderstorms. Cloudy, with a low around 66. East northeast wind 10 to 15 mph, with gusts as high as 20 mph.

    Low: 66 °F

    Chance
    T-storms

  • Friday

    Friday: Showers likely and possibly a thunderstorm. Mostly cloudy, with a high near 77. East wind 10 to 15 mph becoming northwest in the afternoon. Winds could gust as high as 30 mph. Chance of precipitation is 70%.

    High: 77 °F

    Showers
    Likely

Detailed Forecast

This Afternoon
Mostly sunny, with a high near 93. Heat index values as high as 101. South wind 5 to 10 mph.
Tonight
Increasing clouds, with a low around 74. South southeast wind 5 to 10 mph.
Tuesday
Cloudy, then gradually becoming mostly sunny, with a high near 94. Heat index values as high as 102. South wind 5 to 15 mph, with gusts as high as 25 mph.
Tuesday Night
Mostly cloudy, with a low around 72. South southeast wind 5 to 10 mph.
Wednesday
A 30 percent chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 89. South wind around 5 mph becoming northeast in the afternoon.
Wednesday Night
A 30 percent chance of showers and thunderstorms, mainly before 1am. Mostly cloudy, with a low around 67. Northeast wind 5 to 10 mph.
Thursday
A 40 percent chance of showers and thunderstorms. Cloudy, with a high near 82. East wind 5 to 10 mph, with gusts as high as 20 mph.
Thursday Night
A 50 percent chance of showers and thunderstorms. Cloudy, with a low around 66. East northeast wind 10 to 15 mph, with gusts as high as 20 mph.
Friday
Showers likely and possibly a thunderstorm. Mostly cloudy, with a high near 77. East wind 10 to 15 mph becoming northwest in the afternoon. Winds could gust as high as 30 mph. Chance of precipitation is 70%.
Friday Night
A chance of showers and thunderstorms before 1am, then a slight chance of showers. Mostly cloudy, with a low around 55. Chance of precipitation is 40%.
Saturday
A 20 percent chance of showers. Partly sunny, with a high near 69.
Saturday Night
Partly cloudy, with a low around 49.
Sunday
Sunny, with a high near 75.
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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:
1:24 pm CDT Apr 27, 2026
Forecast Valid:
2pm CDT Apr 27, 2026-6pm CDT May 3, 2026
 
Forecast Discussion
 
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Additional Resources

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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