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

Tropical Storm Edouard Impacting the Northwestern Gulf Coast; Hazardous Heat expands in the East

Tropical Storm Edouard will impact the northwestern Gulf Coast through Wednesday with gusty winds, storm surge, and heavy rainfall. Flash and river flooding will be possible, especially in southeastern Texas. Hazardous heat will expand across the central and eastern U.S. by mid-week, and daily chances for severe thunderstorms are expected from the eastern Great Lakes to the Mid-Atlantic this week. Read More >

Current conditions at

San Marcos, San Marcos Municipal Airport (KHYI)

Lat: 29.89°NLon: 97.86°WElev: 597ft.

Fair

85°F

29°C

Humidity 63%
Wind Speed SE 8 mph
Barometer 29.95 in (1013.3 mb)
Dewpoint 71°F (22°C)
Visibility 10.00 mi
Heat Index90°F (32°C)
Last update 1 Sep 9:56 pm CDT
Extended Forecast for

San Marcos TX

  • Tonight

    Tonight: Mostly clear, with a low around 76. East southeast wind around 5 mph becoming calm.

    Low: 76 °F

    Mostly Clear

  • Wednesday

    Wednesday: Mostly sunny and hot, with a high near 99. Heat index values as high as 104. Southwest wind around 5 mph becoming northwest in the afternoon.

    High: 99 °F

    Hot

  • Wednesday Night

    Wednesday Night: Increasing clouds, with a low around 77. East wind 5 to 10 mph becoming south after midnight.

    Low: 77 °F

    Increasing
    Clouds

  • Thursday

    Thursday: Mostly sunny and hot, with a high near 99. Heat index values as high as 103. South wind around 5 mph.

    High: 99 °F

    Hot

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 76. South wind 5 to 10 mph, with gusts as high as 20 mph.

    Low: 76 °F

    Partly Cloudy

  • Friday

    Friday: Mostly sunny, with a high near 96. Calm wind becoming south southeast around 5 mph in the morning.

    High: 96 °F

    Mostly Sunny

  • Friday Night

    Friday Night: Partly cloudy, with a low around 75. Southeast wind 5 to 10 mph becoming light south after midnight.

    Low: 75 °F

    Partly Cloudy

  • Saturday

    Saturday: Mostly sunny, with a high near 97. Calm wind becoming south around 5 mph.

    High: 97 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 76. East southeast wind around 5 mph becoming calm in the evening.

    Low: 76 °F

    Mostly Clear

Detailed Forecast

Tonight
Mostly clear, with a low around 76. East southeast wind around 5 mph becoming calm.
Wednesday
Mostly sunny and hot, with a high near 99. Heat index values as high as 104. Southwest wind around 5 mph becoming northwest in the afternoon.
Wednesday Night
Increasing clouds, with a low around 77. East wind 5 to 10 mph becoming south after midnight.
Thursday
Mostly sunny and hot, with a high near 99. Heat index values as high as 103. South wind around 5 mph.
Thursday Night
Partly cloudy, with a low around 76. South wind 5 to 10 mph, with gusts as high as 20 mph.
Friday
Mostly sunny, with a high near 96. Calm wind becoming south southeast around 5 mph in the morning.
Friday Night
Partly cloudy, with a low around 75. Southeast wind 5 to 10 mph becoming light south after midnight.
Saturday
Mostly sunny, with a high near 97. Calm wind becoming south around 5 mph.
Saturday Night
Mostly clear, with a low around 76. East southeast wind around 5 mph becoming calm in the evening.
Sunday
Sunny, with a high near 97.
Sunday Night
Mostly clear, with a low around 76.
Labor Day
Sunny, with a high near 98.
Monday Night
Mostly clear, with a low around 76.
Tuesday
Sunny, with a high near 98.
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ABOUT THIS FORECAST

 
Point Forecast:
San Marcos TX
 29.88°N 97.91°W (Elev. 597 ft)
Last Update:
8:42 pm CDT Sep 1, 2026
Forecast Valid:
10pm CDT Sep 1, 2026-6pm CDT Sep 8, 2026
 
Forecast Discussion
 
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Additional Resources

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Chance of Precipitation