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

95°F

35°C

Humidity 39%
Wind Speed SW 5 mph
Barometer 30.05 in (1016.6 mb)
Dewpoint 66°F (19°C)
Visibility 10.00 mi
Heat Index98°F (37°C)
Last update 25 Aug 12:56 pm CDT
Extended Forecast for

Mountain City TX

Heat Advisory August 25, 01:55pm until August 26, 07:00pm
Click here for hazard details and duration
Heat Advisory
  •  
    Heat Advisory August 25, 01:55pm until August 26, 07:00pm

    NOW until 7:00pm Wed

    Heat Advisory

  • This Afternoon

    High: 102 °F

    Hot

  • Tonight

    Tonight: Mostly clear, with a low around 75. South southeast wind 5 to 10 mph becoming southwest after midnight. Winds could gust as high as 20 mph.

    Low: 75 °F

    Mostly Clear

  • Wednesday

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

    High: 102 °F

    Hot

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 78. South wind around 5 mph.

    Low: 78 °F

    Mostly Clear

  • Thursday

    Thursday: A 30 percent chance of showers and thunderstorms after 1pm. Sunny and hot, with a high near 100. Southwest wind around 5 mph becoming calm.

    High: 100 °F

    Sunny then
    Chance
    T-storms

  • Thursday Night

    Thursday Night: A chance of showers and thunderstorms before 10pm, then a chance of showers between 10pm and 1am. Partly cloudy, with a low around 77. East northeast wind around 5 mph becoming calm. Chance of precipitation is 40%.

    Low: 77 °F

    Chance
    T-storms then
    Chance
    Showers

  • Friday

    Friday: Sunny and hot, with a high near 100. West wind around 5 mph becoming east northeast in the afternoon.

    High: 100 °F

    Hot

  • Friday Night

    Friday Night: Mostly clear, with a low around 75. East wind around 5 mph becoming south after midnight.

    Low: 75 °F

    Mostly Clear

Detailed Forecast

This Afternoon
Sunny and hot, with a high near 102. Heat index values as high as 106. South southeast wind around 5 mph.
Tonight
Mostly clear, with a low around 75. South southeast wind 5 to 10 mph becoming southwest after midnight. Winds could gust as high as 20 mph.
Wednesday
Sunny and hot, with a high near 102. Heat index values as high as 105. Southwest wind around 5 mph.
Wednesday Night
Mostly clear, with a low around 78. South wind around 5 mph.
Thursday
A 30 percent chance of showers and thunderstorms after 1pm. Sunny and hot, with a high near 100. Southwest wind around 5 mph becoming calm.
Thursday Night
A chance of showers and thunderstorms before 10pm, then a chance of showers between 10pm and 1am. Partly cloudy, with a low around 77. East northeast wind around 5 mph becoming calm. Chance of precipitation is 40%.
Friday
Sunny and hot, with a high near 100. West wind around 5 mph becoming east northeast in the afternoon.
Friday Night
Mostly clear, with a low around 75. East wind around 5 mph becoming south after midnight.
Saturday
Sunny and hot, with a high near 99. Calm wind becoming south southeast around 5 mph in the afternoon.
Saturday Night
Mostly clear, with a low around 74.
Sunday
Sunny and hot, with a high near 99.
Sunday Night
Clear, with a low around 74.
Monday
Sunny, with a high near 98.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Mountain City TX
 30.04°N 97.89°W (Elev. 837 ft)
Last Update:
1:24 pm CDT Aug 25, 2026
Forecast Valid:
1pm CDT Aug 25, 2026-6pm CDT Aug 31, 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