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.

Rain Fog/Mist

58°F

14°C

Humidity 97%
Wind Speed NE 14 mph
Barometer 30.22 in (1023.0 mb)
Dewpoint 57°F (14°C)
Visibility 4.00 mi
Last update 20 Apr 5:56 pm CDT
Extended Forecast for

San Marcos TX

  • Tonight

    Tonight: Showers and possibly a thunderstorm before 1am, then a chance of showers and thunderstorms between 1am and 4am, then showers likely and possibly a thunderstorm after 4am. Low around 58. East wind around 5 mph. Chance of precipitation is 80%. New rainfall amounts between a half and three quarters of an inch possible.

    Low: 58 °F

    Showers

  • Tuesday

    Tuesday: Showers and possibly a thunderstorm, mainly before 4pm, then a chance of showers and thunderstorms after 4pm. High near 68. East wind 5 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 80%. New rainfall amounts between a quarter and half of an inch possible.

    High: 68 °F

    Showers

  • Tuesday Night

    Tuesday Night: A 40 percent chance of showers and thunderstorms. Cloudy, with a low around 63. East southeast wind 5 to 10 mph.

    Low: 63 °F

    Chance
    T-storms

  • Wednesday

    Wednesday: A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 80. Southeast wind around 5 mph.

    High: 80 °F

    Chance
    Showers then
    Chance
    T-storms

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 66. South southeast wind 5 to 10 mph.

    Low: 66 °F

    Mostly Cloudy

  • Thursday

    Thursday: Mostly cloudy, with a high near 84. South wind 5 to 10 mph, with gusts as high as 20 mph.

    High: 84 °F

    Mostly Cloudy

  • Thursday Night

    Thursday Night: Mostly cloudy, with a low around 69. South southeast wind around 10 mph, with gusts as high as 20 mph.

    Low: 69 °F

    Mostly Cloudy

  • Friday

    Friday: A 20 percent chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 87. South southwest wind 5 to 10 mph.

    High: 87 °F

    Cloudy then
    Slight Chance
    T-storms

  • Friday Night

    Friday Night: Partly cloudy, with a low around 69. South wind around 5 mph.

    Low: 69 °F

    Partly Cloudy

Detailed Forecast

Tonight
Showers and possibly a thunderstorm before 1am, then a chance of showers and thunderstorms between 1am and 4am, then showers likely and possibly a thunderstorm after 4am. Low around 58. East wind around 5 mph. Chance of precipitation is 80%. New rainfall amounts between a half and three quarters of an inch possible.
Tuesday
Showers and possibly a thunderstorm, mainly before 4pm, then a chance of showers and thunderstorms after 4pm. High near 68. East wind 5 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 80%. New rainfall amounts between a quarter and half of an inch possible.
Tuesday Night
A 40 percent chance of showers and thunderstorms. Cloudy, with a low around 63. East southeast wind 5 to 10 mph.
Wednesday
A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 80. Southeast wind around 5 mph.
Wednesday Night
Mostly cloudy, with a low around 66. South southeast wind 5 to 10 mph.
Thursday
Mostly cloudy, with a high near 84. South wind 5 to 10 mph, with gusts as high as 20 mph.
Thursday Night
Mostly cloudy, with a low around 69. South southeast wind around 10 mph, with gusts as high as 20 mph.
Friday
A 20 percent chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 87. South southwest wind 5 to 10 mph.
Friday Night
Partly cloudy, with a low around 69. South wind around 5 mph.
Saturday
A 20 percent chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 88.
Saturday Night
Mostly cloudy, with a low around 68.
Sunday
A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 87.
Sunday Night
A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 69.
Monday
A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 88.
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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:
5:32 pm CDT Apr 20, 2026
Forecast Valid:
6pm CDT Apr 20, 2026-6pm CDT Apr 27, 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