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

Heavy Rainfall and Flooding in the Mid-Atlantic; Heat and Wildfire Concerns in the West

Slow moving showers and thunderstorms may result in flash flooding for portions of the mid-Atlantic region through tonight. Meanwhile, excessive heat will continue to build across the West through Tuesday. Heat Advisories and Extreme Heat Warnings are in effect. Fire Weather concerns continue for the West with dry and breezy conditions. Watching the tropics across the Southeast. Read More >

Hazardous Weather Conditions

Current conditions at

San Marcos, San Marcos Municipal Airport (KHYI)

Lat: 29.89°NLon: 97.86°WElev: 597ft.

Fair

85°F

29°C

Humidity 70%
Wind Speed S 9 mph
Barometer 30.00 in (1015.2 mb)
Dewpoint 74°F (23°C)
Visibility 10.00 mi
Heat Index93°F (34°C)
Last update 14 Jul 7:56 pm CDT
Extended Forecast for

San Marcos TX

Flood Watch July 14, 08:22pm until July 15, 07:00am
Click here for hazard details and duration
Flood Watch
  •  
    Flood Watch July 14, 08:22pm until July 15, 07:00am

    NOW until 7:00am Tue

    Flood Watch

  • Tonight

    Low: 75 °F

    Slight Chance
    T-storms then
    Mostly Cloudy

  • Tuesday

    Tuesday: Mostly sunny, with a high near 94. Heat index values as high as 103. South wind 5 to 10 mph, with gusts as high as 20 mph.

    High: 94 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: Increasing clouds, with a low around 74. South southeast wind 5 to 10 mph.

    Low: 74 °F

    Increasing
    Clouds

  • Wednesday

    Wednesday: Mostly sunny, with a high near 96. Heat index values as high as 104. South wind 5 to 10 mph, with gusts as high as 20 mph.

    High: 96 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 72. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.

    Low: 72 °F

    Partly Cloudy

  • Thursday

    Thursday: Mostly sunny, with a high near 95. South wind 5 to 10 mph.

    High: 95 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 72. Southeast wind 5 to 10 mph becoming south southwest after midnight.

    Low: 72 °F

    Partly Cloudy

  • Friday

    Friday: Mostly sunny, with a high near 94. Calm wind becoming south around 5 mph in the morning.

    High: 94 °F

    Mostly Sunny

Detailed Forecast

Tonight
A 20 percent chance of showers and thunderstorms before 10pm. Mostly cloudy, with a low around 75. South wind around 5 mph.
Tuesday
Mostly sunny, with a high near 94. Heat index values as high as 103. South wind 5 to 10 mph, with gusts as high as 20 mph.
Tuesday Night
Increasing clouds, with a low around 74. South southeast wind 5 to 10 mph.
Wednesday
Mostly sunny, with a high near 96. Heat index values as high as 104. South wind 5 to 10 mph, with gusts as high as 20 mph.
Wednesday Night
Partly cloudy, with a low around 72. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.
Thursday
Mostly sunny, with a high near 95. South wind 5 to 10 mph.
Thursday Night
Partly cloudy, with a low around 72. Southeast wind 5 to 10 mph becoming south southwest after midnight.
Friday
Mostly sunny, with a high near 94. Calm wind becoming south around 5 mph in the morning.
Friday Night
Partly cloudy, with a low around 74. Southeast wind around 5 mph.
Saturday
Mostly sunny, with a high near 95.
Saturday Night
Partly cloudy, with a low around 75.
Sunday
Mostly sunny, with a high near 97.
Sunday Night
Partly cloudy, with a low around 74.
Monday
Mostly sunny, with a high near 97.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
San Marcos TX
 29.9°N 97.91°W (Elev. 640 ft)
Last Update:
6:45 pm CDT Jul 14, 2025
Forecast Valid:
8pm CDT Jul 14, 2025-6pm CDT Jul 21, 2025
 
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Additional Resources

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Hourly Weather Forecast

National Digital Forecast Database

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation