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.

Thunderstorm

50°F

10°C

Humidity 86%
Wind Speed N 16 mph
Barometer 30.29 in (1025.5 mb)
Dewpoint 46°F (8°C)
Visibility 10.00 mi
Wind Chill44°F (7°C)
Last update 18 Apr 11:56 pm CDT
Extended Forecast for

San Marcos TX

  • Overnight

    Overnight: Showers and thunderstorms, mainly before 1am. Low around 53. North northeast wind around 15 mph, with gusts as high as 30 mph. Chance of precipitation is 80%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    Low: 53 °F

    T-storms

  • Sunday

    Sunday: Partly sunny, with a high near 72. North northeast wind 10 to 15 mph, with gusts as high as 25 mph.

    High: 72 °F

    Partly Sunny

  • Sunday Night

    Sunday Night: A 30 percent chance of showers, mainly after 4am. Mostly cloudy, with a low around 55. East wind around 5 mph becoming calm in the evening.

    Low: 55 °F

    Mostly Cloudy
    then Chance
    Showers

  • Monday

    Monday: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 7am. Cloudy, with a high near 65. East northeast wind around 5 mph. Chance of precipitation is 70%.

    High: 65 °F

    Showers
    Likely

  • Monday Night

    Monday Night: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Cloudy, with a low around 58. East wind around 5 mph. Chance of precipitation is 60%.

    Low: 58 °F

    Showers
    Likely

  • Tuesday

    Tuesday: Showers and possibly a thunderstorm. High near 69. East wind 5 to 10 mph. Chance of precipitation is 80%.

    High: 69 °F

    Showers

  • Tuesday Night

    Tuesday Night: A 30 percent chance of showers and thunderstorms, mainly before 1am. Cloudy, with a low around 63. Southeast wind 5 to 10 mph.

    Low: 63 °F

    Chance
    Showers

  • Wednesday

    Wednesday: A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 80. Southeast wind 5 to 10 mph.

    High: 80 °F

    Chance
    T-storms

  • Wednesday Night

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

    Low: 66 °F

    Mostly Cloudy

Detailed Forecast

Overnight
Showers and thunderstorms, mainly before 1am. Low around 53. North northeast wind around 15 mph, with gusts as high as 30 mph. Chance of precipitation is 80%. New rainfall amounts of less than a tenth 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 25 mph.
Sunday Night
A 30 percent chance of showers, mainly after 4am. Mostly cloudy, with a low around 55. East wind around 5 mph becoming calm in the evening.
Monday
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 7am. Cloudy, with a high near 65. East northeast wind around 5 mph. Chance of precipitation is 70%.
Monday Night
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Cloudy, with a low around 58. East wind around 5 mph. Chance of precipitation is 60%.
Tuesday
Showers and possibly a thunderstorm. High near 69. East wind 5 to 10 mph. Chance of precipitation is 80%.
Tuesday Night
A 30 percent chance of showers and thunderstorms, mainly before 1am. Cloudy, with a low around 63. Southeast wind 5 to 10 mph.
Wednesday
A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 80. Southeast wind 5 to 10 mph.
Wednesday Night
Mostly cloudy, with a low around 66. South southeast wind around 10 mph.
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 85.
Friday Night
Partly cloudy, with a low around 65.
Saturday
A 20 percent chance of showers and thunderstorms. Partly sunny, with a high near 84.
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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:
12:42 am CDT Apr 19, 2026
Forecast Valid:
12am CDT Apr 19, 2026-6pm CDT Apr 25, 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