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

85°F

29°C

Humidity 70%
Wind Speed S 14 mph
Barometer 30.02 in (1015.6 mb)
Dewpoint 74°F (23°C)
Visibility 10.00 mi
Heat Index93°F (34°C)
Last update 13 Oct 10:56 am CDT
Extended Forecast for

San Marcos TX

  • Today

    Today: Mostly sunny, with a high near 93. Heat index values as high as 101. South wind 10 to 15 mph, with gusts as high as 25 mph.

    High: 93 °F

    Mostly Sunny

  • Tonight

    Tonight: Increasing clouds, with a low around 76. South southeast wind around 10 mph, with gusts as high as 25 mph.

    Low: 76 °F

    Increasing
    Clouds

  • Wednesday

    Wednesday: A slight chance of showers between 10am and 1pm, then a chance of showers and thunderstorms after 1pm. Partly sunny, with a high near 91. Heat index values as high as 101. South southeast wind 10 to 15 mph, with gusts as high as 25 mph. Chance of precipitation is 30%.

    High: 91 °F

    Chance
    Showers

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 69. Southeast wind 5 to 10 mph, with gusts as high as 30 mph.

    Low: 69 °F

    Partly Cloudy

  • Thursday

    Thursday: Mostly sunny, with a high near 89. South southeast wind around 5 mph.

    High: 89 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 66. Calm wind becoming north around 5 mph after midnight.

    Low: 66 °F

    Partly Cloudy

  • Friday

    Friday: Mostly sunny, with a high near 80. North wind around 20 mph, with gusts as high as 35 mph.

    High: 80 °F

    Mostly Sunny

  • Friday Night

    Friday Night: Partly cloudy, with a low around 57. North wind 15 to 20 mph, with gusts as high as 35 mph.

    Low: 57 °F

    Partly Cloudy

  • Saturday

    Saturday: Mostly sunny, with a high near 76. North northeast wind 10 to 20 mph, with gusts as high as 30 mph.

    High: 76 °F

    Mostly Sunny

Detailed Forecast

Today
Mostly sunny, with a high near 93. Heat index values as high as 101. South wind 10 to 15 mph, with gusts as high as 25 mph.
Tonight
Increasing clouds, with a low around 76. South southeast wind around 10 mph, with gusts as high as 25 mph.
Wednesday
A slight chance of showers between 10am and 1pm, then a chance of showers and thunderstorms after 1pm. Partly sunny, with a high near 91. Heat index values as high as 101. South southeast wind 10 to 15 mph, with gusts as high as 25 mph. Chance of precipitation is 30%.
Wednesday Night
Partly cloudy, with a low around 69. Southeast wind 5 to 10 mph, with gusts as high as 30 mph.
Thursday
Mostly sunny, with a high near 89. South southeast wind around 5 mph.
Thursday Night
Partly cloudy, with a low around 66. Calm wind becoming north around 5 mph after midnight.
Friday
Mostly sunny, with a high near 80. North wind around 20 mph, with gusts as high as 35 mph.
Friday Night
Partly cloudy, with a low around 57. North wind 15 to 20 mph, with gusts as high as 35 mph.
Saturday
Mostly sunny, with a high near 76. North northeast wind 10 to 20 mph, with gusts as high as 30 mph.
Saturday Night
Partly cloudy, with a low around 56.
Sunday
Mostly sunny, with a high near 80.
Sunday Night
Partly cloudy, with a low around 60.
Monday
A 20 percent chance of showers. Mostly sunny, with a high near 84.
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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:
11:33 am CDT Oct 13, 2026
Forecast Valid:
11am CDT Oct 13, 2026-6pm CDT Oct 19, 2026
 
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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