Severe Thunderstorms, Excessive Rain and Heat Hazards

A Moderate Risk of severe thunderstorms (level 4 of 5) is in the outlook across portions of the Midwest today. Damaging winds, a few tornadoes and frequent lightning with heavy rainfall are in the forecast. Meanwhile, dangerous heat across the southern Plains into the Great Lakes, mid-Atlantic and Northeast will expand into Friday. Risk for wildfires for the central Rockies and Sacramento Valley. Read More >

Current conditions at

San Marcos, San Marcos Municipal Airport (KHYI)

Lat: 29.89°NLon: 97.86°WElev: 597ft.

Overcast

82°F

28°C

Humidity 82%
Wind Speed S 12 mph
Barometer 29.90 in (1011.8 mb)
Dewpoint 76°F (24°C)
Visibility 10.00 mi
Heat Index89°F (32°C)
Last update 11 Jun 9:56 am CDT
Extended Forecast for

San Marcos TX

  • Today

    Today: Cloudy, then gradually becoming mostly sunny, with a high near 92. Heat index values as high as 103. South wind 10 to 15 mph, with gusts as high as 20 mph.

    High: 92 °F

    Decreasing
    Clouds

  • Tonight

    Tonight: Partly cloudy, with a low around 77. South southeast wind 5 to 15 mph, with gusts as high as 20 mph.

    Low: 77 °F

    Partly Cloudy

  • Friday

    Friday: A 20 percent chance of showers and thunderstorms after 1pm.  Partly sunny, with a high near 92. Heat index values as high as 102. Southeast wind 5 to 10 mph.

    High: 92 °F

    Mostly Cloudy
    then Slight
    Chance
    T-storms

  • Friday Night

    Friday Night: Partly cloudy, with a low around 75. South southeast wind 5 to 10 mph.

    Low: 75 °F

    Partly Cloudy

  • Saturday

    Saturday: Mostly sunny, with a high near 93. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.

    High: 93 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: Partly cloudy, with a low around 76. South southeast wind 5 to 15 mph, with gusts as high as 20 mph.

    Low: 76 °F

    Partly Cloudy

  • Sunday

    Sunday: Showers likely and possibly a thunderstorm after 1pm.  Mostly sunny, with a high near 92. South southeast wind around 5 mph.  Chance of precipitation is 60%.

    High: 92 °F

    Partly Sunny
    then Showers
    Likely

  • Sunday Night

    Sunday Night: A 50 percent chance of showers and thunderstorms.  Mostly cloudy, with a low around 75. South southeast wind 5 to 10 mph.

    Low: 75 °F

    Chance
    T-storms

  • Monday

    Monday: Showers likely and possibly a thunderstorm.  Partly sunny, with a high near 89. South wind around 5 mph.  Chance of precipitation is 70%.

    High: 89 °F

    Showers
    Likely

Detailed Forecast

Today
Cloudy, then gradually becoming mostly sunny, with a high near 92. Heat index values as high as 103. South wind 10 to 15 mph, with gusts as high as 20 mph.
Tonight
Partly cloudy, with a low around 77. South southeast wind 5 to 15 mph, with gusts as high as 20 mph.
Friday
A 20 percent chance of showers and thunderstorms after 1pm. Partly sunny, with a high near 92. Heat index values as high as 102. Southeast wind 5 to 10 mph.
Friday Night
Partly cloudy, with a low around 75. South southeast wind 5 to 10 mph.
Saturday
Mostly sunny, with a high near 93. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.
Saturday Night
Partly cloudy, with a low around 76. South southeast wind 5 to 15 mph, with gusts as high as 20 mph.
Sunday
Showers likely and possibly a thunderstorm after 1pm. Mostly sunny, with a high near 92. South southeast wind around 5 mph. Chance of precipitation is 60%.
Sunday Night
A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 75. South southeast wind 5 to 10 mph.
Monday
Showers likely and possibly a thunderstorm. Partly sunny, with a high near 89. South wind around 5 mph. Chance of precipitation is 70%.
Monday Night
Showers likely and possibly a thunderstorm. Mostly cloudy, with a low around 72. Chance of precipitation is 60%.
Tuesday
A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 86.
Tuesday Night
A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 73.
Wednesday
A 20 percent chance of showers and thunderstorms. Partly sunny, with a high near 91.
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ABOUT THIS FORECAST

 
Point Forecast:
San Marcos TX
 29.88°N 97.94°W (Elev. 577 ft)
6:46 am CDT Jun 11, 2026
10am CDT Jun 11, 2026-6pm CDT Jun 17, 2026
 
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Additional Resources

Radar & Satellite Image

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Hourly Weather Forecast

National Digital Forecast Database