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

78°F

26°C

Humidity 48%
Wind Speed NE 7 mph
Barometer 29.91 in (1012.0 mb)
Dewpoint 57°F (14°C)
Visibility 10.00 mi
Heat Index79°F (26°C)
Last update 20 May 10:56 pm CDT
Extended Forecast for

San Marcos TX

  • Tonight

    Tonight: Partly cloudy, with a low around 66. North northeast wind around 5 mph.

    Low: 66 °F

    Partly Cloudy

  • Wednesday

    Wednesday: Mostly sunny, with a high near 96. North northeast wind around 5 mph becoming southeast in the afternoon.

    High: 96 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 70. East southeast wind around 5 mph becoming south after midnight.

    Low: 70 °F

    Partly Cloudy

  • Thursday

    Thursday: Mostly sunny, with a high near 97. Heat index values as high as 100. Light south wind becoming south southeast 5 to 10 mph in the morning.

    High: 97 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 70. South southeast wind 5 to 10 mph.

    Low: 70 °F

    Partly Cloudy

  • Friday

    Friday: Mostly sunny, with a high near 96. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.

    High: 96 °F

    Mostly Sunny

  • Friday Night

    Friday Night: Partly cloudy, with a low around 73. South wind 10 to 15 mph, with gusts as high as 20 mph.

    Low: 73 °F

    Partly Cloudy

  • Saturday

    Saturday: Mostly sunny, with a high near 98. South wind 10 to 15 mph, with gusts as high as 25 mph.

    High: 98 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: Partly cloudy, with a low around 75. South southeast wind 10 to 15 mph, with gusts as high as 25 mph.

    Low: 75 °F

    Partly Cloudy

Detailed Forecast

Tonight
Partly cloudy, with a low around 66. North northeast wind around 5 mph.
Wednesday
Mostly sunny, with a high near 96. North northeast wind around 5 mph becoming southeast in the afternoon.
Wednesday Night
Partly cloudy, with a low around 70. East southeast wind around 5 mph becoming south after midnight.
Thursday
Mostly sunny, with a high near 97. Heat index values as high as 100. Light south wind becoming south southeast 5 to 10 mph in the morning.
Thursday Night
Partly cloudy, with a low around 70. South southeast wind 5 to 10 mph.
Friday
Mostly sunny, with a high near 96. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.
Friday Night
Partly cloudy, with a low around 73. South wind 10 to 15 mph, with gusts as high as 20 mph.
Saturday
Mostly sunny, with a high near 98. South wind 10 to 15 mph, with gusts as high as 25 mph.
Saturday Night
Partly cloudy, with a low around 75. South southeast wind 10 to 15 mph, with gusts as high as 25 mph.
Sunday
A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 97.
Sunday Night
A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 72.
Memorial Day
A 40 percent chance of showers and thunderstorms. Partly sunny, with a high near 91.
Monday Night
A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 67.
Tuesday
A 30 percent chance of showers and thunderstorms. Partly sunny, with a high near 85.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
San Marcos TX
 29.88°N 97.94°W (Elev. 577 ft)
Last Update:
3:52 pm CDT May 20, 2025
Forecast Valid:
11pm CDT May 20, 2025-6pm CDT May 27, 2025
 
Forecast Discussion
 
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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