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

73°F

23°C

Humidity 96%
Wind Speed S 3 mph
Barometer 30.00 in (1014.9 mb)
Dewpoint 72°F (22°C)
Visibility 10.00 mi
Last update 27 Jul 4:56 am CDT
Extended Forecast for

San Marcos TX

  • Today

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

    High: 97 °F

    Sunny

  • Tonight

    Tonight: 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

  • Friday

    Friday: Mostly sunny and hot, with a high near 100. South southwest wind around 5 mph.

    High: 100 °F

    Hot

Detailed Forecast

Today
Sunny, with a high near 97. Heat index values as high as 101. South wind 5 to 10 mph.
Tonight
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. South southwest wind around 5 mph.
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.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
San Marcos TX
 29.88°N 97.94°W (Elev. 577 ft)
Last Update:
5:32 am CDT Jul 27, 2026
Forecast Valid:
5am CDT Jul 27, 2026-6pm CDT Aug 2, 2026
 
Forecast Discussion
 
Get as KML Get as XML

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