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 with Haze

78°F

26°C

Humidity 85%
Wind Speed S 3 mph
Barometer 30.00 in (1015.1 mb)
Dewpoint 73°F (23°C)
Visibility 10.00 mi
Heat Index80°F (27°C)
Last update 27 Jul 1:56 am CDT
Extended Forecast for

San Marcos TX

  • Overnight

    Overnight: Clear, with a low around 75. South wind around 5 mph.

    Low: 75 °F

    Clear

  • Monday

    Monday: Sunny, with a high near 97. Heat index values as high as 101. South wind 5 to 10 mph.

    High: 97 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 74. South wind 5 to 10 mph, with gusts as high as 20 mph.

    Low: 74 °F

    Mostly Clear

  • Tuesday

    Tuesday: Mostly cloudy through mid morning, then gradual clearing, with a high near 97. Heat index values as high as 103. South wind 5 to 10 mph.

    High: 97 °F

    Becoming
    Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 75. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.

    Low: 75 °F

    Mostly Clear

  • Wednesday

    Wednesday: Mostly sunny, with a high near 98. South wind around 5 mph.

    High: 98 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 76. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.

    Low: 76 °F

    Partly Cloudy

  • Thursday

    Thursday: Mostly sunny and hot, with a high near 99. South southwest wind around 5 mph.

    High: 99 °F

    Hot

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 76. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.

    Low: 76 °F

    Partly Cloudy

Detailed Forecast

Overnight
Clear, with a low around 75. South wind around 5 mph.
Monday
Sunny, with a high near 97. Heat index values as high as 101. South wind 5 to 10 mph.
Monday Night
Mostly clear, with a low around 74. South wind 5 to 10 mph, with gusts as high as 20 mph.
Tuesday
Mostly cloudy through mid morning, then gradual clearing, with a high near 97. Heat index values as high as 103. South wind 5 to 10 mph.
Tuesday Night
Mostly clear, with a low around 75. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.
Wednesday
Mostly sunny, with a high near 98. South wind around 5 mph.
Wednesday Night
Partly cloudy, with a low around 76. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.
Thursday
Mostly sunny and hot, with a high near 99. South southwest wind around 5 mph.
Thursday Night
Partly cloudy, with a low around 76. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.
Friday
Mostly sunny and hot, with a high near 100.
Friday Night
Partly cloudy, with a low around 78.
Saturday
Mostly sunny and hot, with a high near 100.
Saturday Night
Partly cloudy, with a low around 79.
Sunday
Mostly sunny, with a high near 98.
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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:
2:44 am CDT Jul 27, 2026
Forecast Valid:
2am CDT Jul 27, 2026-6pm CDT Aug 2, 2026
 
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Additional Resources

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Chance of Precipitation