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

Tropical Storm Arthur and Heavy Rainfall in the South; Severe Weather in the Midwest

An outbreak of severe thunderstorms is expected across portions of Illinois and Indiana tonight. Intense tornadoes, swaths of damaging gusts, and hail in excess of 2 inches in diameter possible. Tropical Storm Arthur will continue to produce strong winds across coastal Upper Texas and Louisiana tonight, as well as potentially life-threatening flooding across southern Louisiana into Mississippi. 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 77%
Wind Speed SE 6 mph
Barometer 29.62 in (1002.3 mb)
Dewpoint 77°F (25°C)
Visibility 10.00 mi
Heat Index96°F (36°C)
Last update 17 Jun 7:56 pm CDT
Extended Forecast for

Martindale TX

Extreme Heat Warning June 18, 12:00pm until June 18, 08:00pm
Click here for hazard details and duration
Extreme Heat Warning

  • Tonight

    Tonight: Mostly clear, with a low around 77. East southeast wind 5 to 10 mph becoming south after midnight.

    Low: 77 °F

    Mostly Clear

  • Thursday

    Thursday: Mostly cloudy, then gradually becoming sunny, with a high near 95. Heat index values as high as 112. South southeast wind 5 to 15 mph, with gusts as high as 20 mph.

    High: 95 °F

    Decreasing
    Clouds

  • Thursday Night

    Thursday Night: Increasing clouds, with a low around 79. Southeast wind 10 to 15 mph, with gusts as high as 20 mph.

    Low: 79 °F

    Increasing
    Clouds

  • Juneteenth

    Juneteenth: Partly sunny, with a high near 92. Heat index values as high as 106. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.

    High: 92 °F

    Partly Sunny

  • Friday Night

    Friday Night: A chance of showers and thunderstorms before 1am, then a slight chance of showers between 1am and 4am, then a slight chance of showers and thunderstorms after 4am. Mostly cloudy, with a low around 78. South southeast wind 5 to 10 mph. Chance of precipitation is 30%.

    Low: 78 °F

    Chance
    T-storms then
    Chance
    Showers

  • Saturday

    Saturday: A 50 percent chance of showers and thunderstorms, mainly after 1pm. Partly sunny, with a high near 92. South wind 5 to 10 mph, with gusts as high as 20 mph.

    High: 92 °F

    Slight Chance
    T-storms then
    Chance
    T-storms

  • Saturday Night

    Saturday Night: A 20 percent chance of showers and thunderstorms before 1am. Partly cloudy, with a low around 77. South southeast wind around 10 mph.

    Low: 77 °F

    Slight Chance
    T-storms

  • Sunday

    Sunday: Partly sunny, with a high near 94. South wind 10 to 15 mph, with gusts as high as 25 mph.

    High: 94 °F

    Partly Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 77. South southeast wind around 15 mph, with gusts as high as 25 mph.

    Low: 77 °F

    Mostly Clear

Detailed Forecast

Tonight
Mostly clear, with a low around 77. East southeast wind 5 to 10 mph becoming south after midnight.
Thursday
Mostly cloudy, then gradually becoming sunny, with a high near 95. Heat index values as high as 112. South southeast wind 5 to 15 mph, with gusts as high as 20 mph.
Thursday Night
Increasing clouds, with a low around 79. Southeast wind 10 to 15 mph, with gusts as high as 20 mph.
Juneteenth
Partly sunny, with a high near 92. Heat index values as high as 106. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.
Friday Night
A chance of showers and thunderstorms before 1am, then a slight chance of showers between 1am and 4am, then a slight chance of showers and thunderstorms after 4am. Mostly cloudy, with a low around 78. South southeast wind 5 to 10 mph. Chance of precipitation is 30%.
Saturday
A 50 percent chance of showers and thunderstorms, mainly after 1pm. Partly sunny, with a high near 92. South wind 5 to 10 mph, with gusts as high as 20 mph.
Saturday Night
A 20 percent chance of showers and thunderstorms before 1am. Partly cloudy, with a low around 77. South southeast wind around 10 mph.
Sunday
Partly sunny, with a high near 94. South wind 10 to 15 mph, with gusts as high as 25 mph.
Sunday Night
Mostly clear, with a low around 77. South southeast wind around 15 mph, with gusts as high as 25 mph.
Monday
Mostly sunny, with a high near 96.
Monday Night
Mostly clear, with a low around 77.
Tuesday
Mostly sunny, with a high near 95.
Tuesday Night
Partly cloudy, with a low around 76.
Wednesday
Mostly sunny, with a high near 97.
Basemap Options
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Martindale TX
 29.86°N 97.83°W (Elev. 548 ft)
Last Update:
8:12 pm CDT Jun 17, 2026
Forecast Valid:
8pm CDT Jun 17, 2026-6pm CDT Jun 24, 2026
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

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