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.

Light Rain

74°F

23°C

Humidity 94%
Wind Speed NW 5 mph
Barometer 30.02 in (1015.5 mb)
Dewpoint 72°F (22°C)
Visibility 10.00 mi
Last update 28 Aug 8:56 pm CDT
Extended Forecast for

San Marcos TX

Flood Advisory until August 28, 11:45pm
Click here for hazard details and duration
Flood Advisory
  •  
    Flood Advisory until August 28, 11:45pm

    NOW until 11:45pm Fri

    Flood Advisory

  • Tonight

    Low: 75 °F

    Chance
    Showers

  • Saturday

    Saturday: Sunny, with a high near 98. Heat index values as high as 104. Calm wind becoming southeast around 5 mph in the afternoon.

    High: 98 °F

    Sunny

  • Saturday Night

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

    Low: 75 °F

    Mostly Clear

  • Sunday

    Sunday: Mostly cloudy through mid morning, then gradual clearing, with a high near 98. Heat index values as high as 104. Calm wind becoming south around 5 mph in the afternoon.

    High: 98 °F

    Becoming
    Sunny

  • Sunday Night

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

    Low: 75 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 98. Calm wind becoming south around 5 mph in the morning.

    High: 98 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 76. Southeast wind 5 to 10 mph.

    Low: 76 °F

    Mostly Clear

  • Tuesday

    Tuesday: Mostly sunny, with a high near 98. Calm wind becoming south around 5 mph in the morning.

    High: 98 °F

    Mostly Sunny

Detailed Forecast

Tonight
A 30 percent chance of showers, mainly before 10pm. Mostly clear, with a low around 75. South southeast wind around 5 mph becoming calm in the evening.
Saturday
Sunny, with a high near 98. Heat index values as high as 104. Calm wind becoming southeast around 5 mph in the afternoon.
Saturday Night
Mostly clear, with a low around 75. South southeast wind around 5 mph.
Sunday
Mostly cloudy through mid morning, then gradual clearing, with a high near 98. Heat index values as high as 104. Calm wind becoming south around 5 mph in the afternoon.
Sunday Night
Mostly clear, with a low around 75. South southeast wind 5 to 10 mph.
Monday
Sunny, with a high near 98. Calm wind becoming south around 5 mph in the morning.
Monday Night
Mostly clear, with a low around 76. Southeast wind 5 to 10 mph.
Tuesday
Mostly sunny, with a high near 98. Calm wind becoming south around 5 mph in the morning.
Tuesday Night
Mostly clear, with a low around 76. Southeast wind 5 to 10 mph.
Wednesday
Mostly sunny, with a high near 98.
Wednesday Night
Mostly clear, with a low around 76.
Thursday
Mostly sunny, with a high near 98.
Thursday Night
Mostly clear, with a low around 76.
Friday
Sunny, with a high near 98.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
San Marcos TX
 29.88°N 97.94°W (Elev. 577 ft)
Last Update:
6:42 pm CDT Aug 28, 2026
Forecast Valid:
9pm CDT Aug 28, 2026-6pm CDT Sep 4, 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