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

86°F

30°C

Humidity 49%
Wind Speed SE 5 mph
Barometer 29.87 in (1010.7 mb)
Dewpoint 65°F (18°C)
Visibility 10.00 mi
Heat Index88°F (31°C)
Last update 20 Sep 7:56 pm CDT
Extended Forecast for

Mountain City TX

  • Tonight

    Tonight: Mostly cloudy, with a low around 74. South southwest wind around 5 mph.

    Low: 74 °F

    Mostly Cloudy

  • Monday

    Monday: Partly sunny, then gradually becoming sunny, with a high near 97. Heat index values as high as 104. Calm wind becoming south around 5 mph.

    High: 97 °F

    Becoming
    Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 73. East northeast wind around 5 mph becoming calm in the evening.

    Low: 73 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Mostly sunny, with a high near 97. Heat index values as high as 102. Calm wind becoming east around 5 mph in the afternoon.

    High: 97 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: A slight chance of showers and thunderstorms before 10pm, then a slight chance of showers between 10pm and 1am. Partly cloudy, with a low around 74. East wind around 5 mph becoming calm in the evening. Chance of precipitation is 20%.

    Low: 74 °F

    Slight Chance
    T-storms then
    Slight Chance
    Showers

  • Wednesday

    Wednesday: Mostly sunny, with a high near 97. Calm wind becoming east around 5 mph in the afternoon.

    High: 97 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 74. East wind around 5 mph becoming calm in the evening.

    Low: 74 °F

    Partly Cloudy

  • Thursday

    Thursday: Mostly sunny, with a high near 96. Light north northeast wind becoming east 5 to 10 mph in the morning.

    High: 96 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 72. East southeast wind around 5 mph becoming calm in the evening.

    Low: 72 °F

    Partly Cloudy

Detailed Forecast

Tonight
Mostly cloudy, with a low around 74. South southwest wind around 5 mph.
Monday
Partly sunny, then gradually becoming sunny, with a high near 97. Heat index values as high as 104. Calm wind becoming south around 5 mph.
Monday Night
Partly cloudy, with a low around 73. East northeast wind around 5 mph becoming calm in the evening.
Tuesday
Mostly sunny, with a high near 97. Heat index values as high as 102. Calm wind becoming east around 5 mph in the afternoon.
Tuesday Night
A slight chance of showers and thunderstorms before 10pm, then a slight chance of showers between 10pm and 1am. Partly cloudy, with a low around 74. East wind around 5 mph becoming calm in the evening. Chance of precipitation is 20%.
Wednesday
Mostly sunny, with a high near 97. Calm wind becoming east around 5 mph in the afternoon.
Wednesday Night
Partly cloudy, with a low around 74. East wind around 5 mph becoming calm in the evening.
Thursday
Mostly sunny, with a high near 96. Light north northeast wind becoming east 5 to 10 mph in the morning.
Thursday Night
Partly cloudy, with a low around 72. East southeast wind around 5 mph becoming calm in the evening.
Friday
Mostly sunny, with a high near 95.
Friday Night
Partly cloudy, with a low around 71.
Saturday
Mostly sunny, with a high near 95.
Saturday Night
Partly cloudy, with a low around 72.
Sunday
Mostly sunny, with a high near 96.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Mountain City TX
 30.02°N 97.89°W (Elev. 797 ft)
Last Update:
8:02 pm CDT Sep 20, 2026
Forecast Valid:
8pm CDT Sep 20, 2026-6pm CDT Sep 27, 2026
 
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Additional Resources

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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