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.

Overcast

59°F

15°C

Humidity 83%
Wind Speed E 5 mph
Barometer 30.22 in (1022.9 mb)
Dewpoint 54°F (12°C)
Visibility 10.00 mi
Last update 20 Apr 2:56 am CDT
Extended Forecast for

San Marcos TX

  • Overnight

    Overnight: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 4am. Cloudy, with a low around 55. North northeast wind around 5 mph becoming calm. Chance of precipitation is 60%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    Low: 55 °F

    Showers
    Likely

  • Monday

    Monday: Showers and possibly a thunderstorm. High near 62. Northeast wind 5 to 10 mph. Chance of precipitation is 90%. New rainfall amounts between a quarter and half of an inch possible.

    High: 62 °F

    Showers

  • Monday Night

    Monday Night: Showers likely and possibly a thunderstorm before 1am, then a chance of showers and thunderstorms between 1am and 4am, then showers and possibly a thunderstorm after 4am. Low around 57. East northeast wind around 5 mph. Chance of precipitation is 80%. New rainfall amounts between a quarter and half of an inch possible.

    Low: 57 °F

    Showers

  • Tuesday

    Tuesday: Showers and possibly a thunderstorm. High near 68. East wind 5 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 90%.

    High: 68 °F

    Showers

  • Tuesday Night

    Tuesday Night: A 40 percent chance of showers and thunderstorms. Cloudy, with a low around 64. Southeast wind 5 to 10 mph.

    Low: 64 °F

    Chance
    T-storms

  • Wednesday

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

    High: 80 °F

    Chance
    T-storms

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 66. 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

Detailed Forecast

Overnight
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 4am. Cloudy, with a low around 55. North northeast wind around 5 mph becoming calm. Chance of precipitation is 60%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Monday
Showers and possibly a thunderstorm. High near 62. Northeast wind 5 to 10 mph. Chance of precipitation is 90%. New rainfall amounts between a quarter and half of an inch possible.
Monday Night
Showers likely and possibly a thunderstorm before 1am, then a chance of showers and thunderstorms between 1am and 4am, then showers and possibly a thunderstorm after 4am. Low around 57. East northeast wind around 5 mph. Chance of precipitation is 80%. New rainfall amounts between a quarter and half of an inch possible.
Tuesday
Showers and possibly a thunderstorm. High near 68. East wind 5 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 90%.
Tuesday Night
A 40 percent chance of showers and thunderstorms. Cloudy, with a low around 64. Southeast wind 5 to 10 mph.
Wednesday
A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 80. South southeast wind around 5 mph.
Wednesday Night
Mostly cloudy, with a low around 66. 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.
Friday Night
Mostly cloudy, with a low around 68.
Saturday
A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 87.
Saturday Night
Mostly cloudy, with a low around 69.
Sunday
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:
2:44 am CDT Apr 20, 2026
Forecast Valid:
3am CDT Apr 20, 2026-6pm CDT Apr 26, 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