National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Hazardous Weather Conditions

Current conditions at

San Marcos, San Marcos Municipal Airport (KHYI)

Lat: 29.89°NLon: 97.86°WElev: 597ft.

Fair

82°F

28°C

Humidity 56%
Wind Speed S 5 mph
Barometer 30.01 in (1015.3 mb)
Dewpoint 65°F (18°C)
Visibility 10.00 mi
Heat Index84°F (29°C)
Last update 23 Aug 1:56 am CDT
Extended Forecast for

3 Miles W San Marcos TX

Heat Advisory August 23, 02:44am until August 26, 07:00pm
Click here for hazard details and duration
Heat Advisory
  •  
    Heat Advisory August 23, 02:44am until August 26, 07:00pm

    NOW until 7:00pm Wed

    Heat Advisory

  • Overnight

    Low: 76 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny and hot, with a high near 104. West southwest wind around 5 mph becoming south southeast in the afternoon.

    High: 104 °F

    Hot

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 75. South southeast wind 5 to 10 mph becoming southwest after midnight.

    Low: 75 °F

    Mostly Clear

  • Monday

    Monday: Sunny and hot, with a high near 102. Heat index values as high as 105. Southwest wind around 5 mph.

    High: 102 °F

    Hot

  • Monday Night

    Monday Night: Mostly clear, with a low around 74. South southeast wind 5 to 10 mph.

    Low: 74 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny and hot, with a high near 101. South southwest wind around 5 mph.

    High: 101 °F

    Hot

  • Tuesday Night

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

    Low: 75 °F

    Mostly Clear

  • Wednesday

    Wednesday: Sunny and hot, with a high near 102. South southwest wind around 5 mph.

    High: 102 °F

    Hot

Detailed Forecast

Overnight
Mostly clear, with a low around 76. South southwest wind around 5 mph.
Sunday
Sunny and hot, with a high near 104. West southwest wind around 5 mph becoming south southeast in the afternoon.
Sunday Night
Mostly clear, with a low around 75. South southeast wind 5 to 10 mph becoming southwest after midnight.
Monday
Sunny and hot, with a high near 102. Heat index values as high as 105. Southwest wind around 5 mph.
Monday Night
Mostly clear, with a low around 74. South southeast wind 5 to 10 mph.
Tuesday
Sunny and hot, with a high near 101. South southwest wind around 5 mph.
Tuesday Night
Mostly clear, with a low around 75. South southeast wind 5 to 10 mph.
Wednesday
Sunny and hot, with a high near 102. South southwest wind around 5 mph.
Wednesday Night
Mostly clear, with a low around 77. South southeast wind around 5 mph.
Thursday
A 20 percent chance of showers and thunderstorms after 1pm. Sunny and hot, with a high near 102.
Thursday Night
Partly cloudy, with a low around 76.
Friday
Mostly sunny and hot, with a high near 100.
Friday Night
Mostly clear, with a low around 75.
Saturday
Sunny and hot, with a high near 99.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
3 Miles W San Marcos TX
 29.88°N 97.99°W (Elev. 725 ft)
Last Update:
1:28 am CDT Aug 23, 2026
Forecast Valid:
2am CDT Aug 23, 2026-6pm CDT Aug 29, 2026
 
Forecast Discussion
 
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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