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

94°F

34°C

Humidity 51%
Wind Speed S 17 mph
Barometer 29.93 in (1012.5 mb)
Dewpoint 73°F (23°C)
Visibility 10.00 mi
Heat Index104°F (40°C)
Last update 13 Oct 2:56 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 around 15 mph, with gusts as high as 25 mph.

    High: 93 °F

    Mostly Sunny

  • Tonight

    Tonight: Increasing clouds, with a low around 76. South 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 92. Heat index values as high as 101. South wind around 10 mph, with gusts as high as 25 mph. Chance of precipitation is 50%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    High: 92 °F

    Slight Chance
    Showers then
    Chance
    T-storms

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 69. South 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: Mostly clear, with a low around 68. Calm wind becoming north around 5 mph after midnight.

    Low: 68 °F

    Mostly Clear

  • Friday

    Friday: Mostly sunny, with a high near 78. North wind around 20 mph, with gusts as high as 35 mph.

    High: 78 °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 40 mph.

    Low: 57 °F

    Partly Cloudy

  • Saturday

    Saturday: Mostly sunny, with a high near 74. North northeast wind 10 to 20 mph, with gusts as high as 30 mph.

    High: 74 °F

    Mostly Sunny

Detailed Forecast

This Afternoon
Mostly sunny, with a high near 93. Heat index values as high as 101. South wind around 15 mph, with gusts as high as 25 mph.
Tonight
Increasing clouds, with a low around 76. South 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 92. Heat index values as high as 101. South wind around 10 mph, with gusts as high as 25 mph. Chance of precipitation is 50%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Wednesday Night
Partly cloudy, with a low around 69. South 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
Mostly clear, with a low around 68. Calm wind becoming north around 5 mph after midnight.
Friday
Mostly sunny, with a high near 78. 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 40 mph.
Saturday
Mostly sunny, with a high near 74. North northeast wind 10 to 20 mph, with gusts as high as 30 mph.
Saturday Night
Mostly clear, with a low around 54.
Sunday
Mostly sunny, with a high near 78.
Sunday Night
Mostly cloudy, with a low around 59.
Monday
Partly sunny, with a high near 83.
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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:
2:46 pm CDT Oct 13, 2026
Forecast Valid:
3pm CDT Oct 13, 2026-6pm CDT Oct 19, 2026
 
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Additional Resources

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Chance of Precipitation