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

62°F

17°C

Humidity 73%
Wind Speed N 16 G 28 mph
Barometer 30.10 in (1018.6 mb)
Dewpoint 53°F (12°C)
Visibility 10.00 mi
Last update 18 Apr 2:56 pm CDT
Extended Forecast for

San Marcos TX

  • This Afternoon

    This Afternoon: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 4pm. Cloudy, with a steady temperature around 62. North wind around 20 mph, with gusts as high as 30 mph. Chance of precipitation is 70%.

    High: 62 °F

    Showers
    Likely

  • Tonight

    Tonight: Showers likely and possibly a thunderstorm before 1am, then a chance of showers between 1am and 4am. Mostly cloudy, with a low around 53. North northeast wind 10 to 20 mph, with gusts as high as 35 mph. Chance of precipitation is 70%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

    Low: 53 °F

    Showers
    Likely

  • Sunday

    Sunday: Partly sunny, with a high near 72. North northeast wind 10 to 15 mph, with gusts as high as 20 mph.

    High: 72 °F

    Partly Sunny

  • Sunday Night

    Sunday Night: A 30 percent chance of showers after 1am. Mostly cloudy, with a low around 56. East wind around 5 mph becoming calm in the evening.

    Low: 56 °F

    Mostly Cloudy
    then Chance
    Showers

  • Monday

    Monday: Showers likely and possibly a thunderstorm. Cloudy, with a high near 64. East northeast wind around 5 mph. Chance of precipitation is 60%.

    High: 64 °F

    Showers
    Likely

  • Monday Night

    Monday Night: A 50 percent chance of showers and thunderstorms. Cloudy, with a low around 57. East wind around 5 mph.

    Low: 57 °F

    Chance
    Showers then
    Chance
    T-storms

  • Tuesday

    Tuesday: Showers and possibly a thunderstorm. High near 70. East wind 5 to 10 mph. Chance of precipitation is 80%.

    High: 70 °F

    Showers

  • Tuesday Night

    Tuesday Night: A 20 percent chance of showers and thunderstorms before 1am. Mostly cloudy, with a low around 63. Southeast wind 5 to 10 mph.

    Low: 63 °F

    Slight Chance
    T-storms

  • Wednesday

    Wednesday: A 30 percent chance of showers and thunderstorms, mainly after 1pm. Mostly cloudy, with a high near 81. Southeast wind 5 to 10 mph.

    High: 81 °F

    Chance
    T-storms

Detailed Forecast

This Afternoon
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 4pm. Cloudy, with a steady temperature around 62. North wind around 20 mph, with gusts as high as 30 mph. Chance of precipitation is 70%.
Tonight
Showers likely and possibly a thunderstorm before 1am, then a chance of showers between 1am and 4am. Mostly cloudy, with a low around 53. North northeast wind 10 to 20 mph, with gusts as high as 35 mph. Chance of precipitation is 70%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Sunday
Partly sunny, with a high near 72. North northeast wind 10 to 15 mph, with gusts as high as 20 mph.
Sunday Night
A 30 percent chance of showers after 1am. Mostly cloudy, with a low around 56. East wind around 5 mph becoming calm in the evening.
Monday
Showers likely and possibly a thunderstorm. Cloudy, with a high near 64. East northeast wind around 5 mph. Chance of precipitation is 60%.
Monday Night
A 50 percent chance of showers and thunderstorms. Cloudy, with a low around 57. East wind around 5 mph.
Tuesday
Showers and possibly a thunderstorm. High near 70. East wind 5 to 10 mph. Chance of precipitation is 80%.
Tuesday Night
A 20 percent chance of showers and thunderstorms before 1am. Mostly cloudy, with a low around 63. Southeast wind 5 to 10 mph.
Wednesday
A 30 percent chance of showers and thunderstorms, mainly after 1pm. Mostly cloudy, with a high near 81. Southeast wind 5 to 10 mph.
Wednesday Night
Mostly cloudy, with a low around 67.
Thursday
Mostly cloudy, with a high near 83.
Thursday Night
Mostly cloudy, with a low around 69.
Friday
A 30 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 86.
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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:
2:46 pm CDT Apr 18, 2026
Forecast Valid:
3pm CDT Apr 18, 2026-6pm CDT Apr 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