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

83°F

28°C

Humidity 61%
Wind Speed SE 14 G 20 mph
Barometer 30.03 in (1015.9 mb)
Dewpoint 68°F (20°C)
Visibility 10.00 mi
Heat Index86°F (30°C)
Last update 16 Apr 11:56 am CDT
Extended Forecast for

San Marcos TX

  • This Afternoon

    This Afternoon: Mostly sunny, with a high near 88. South wind around 10 mph, with gusts as high as 20 mph.

    High: 88 °F

    Mostly Sunny

  • Tonight

    Tonight: Increasing clouds, with a low around 68. South southeast wind around 10 mph, with gusts as high as 20 mph.

    Low: 68 °F

    Increasing
    Clouds

  • Friday

    Friday: Cloudy, then gradually becoming mostly sunny, with a high near 89. South wind 10 to 15 mph, with gusts as high as 30 mph.

    High: 89 °F

    Decreasing
    Clouds

  • Friday Night

    Friday Night: Mostly cloudy, with a low around 67. South southeast wind 5 to 15 mph, with gusts as high as 30 mph.

    Low: 67 °F

    Mostly Cloudy

  • Saturday

    Saturday: A 50 percent chance of showers and thunderstorms, mainly after 1pm. Cloudy, with a high near 77. South southeast wind 5 to 15 mph becoming north in the afternoon. Winds could gust as high as 25 mph.

    High: 77 °F

    Slight Chance
    T-storms then
    Chance
    T-storms

  • Saturday Night

    Saturday Night: Showers likely and possibly a thunderstorm before 1am, then a chance of showers. Cloudy, with a low around 54. North northeast wind around 15 mph, with gusts as high as 30 mph. Chance of precipitation is 60%.

    Low: 54 °F

    Showers
    Likely

  • Sunday

    Sunday: A 20 percent chance of showers. Mostly cloudy, with a high near 69. North northeast wind 10 to 15 mph, with gusts as high as 25 mph.

    High: 69 °F

    Slight Chance
    Showers

  • Sunday Night

    Sunday Night: A 30 percent chance of showers, mainly after 1am. Cloudy, with a low around 54. East northeast wind 5 to 10 mph.

    Low: 54 °F

    Chance
    Showers

  • Monday

    Monday: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1pm. Cloudy, with a high near 65. East northeast wind 5 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 60%.

    High: 65 °F

    Showers
    Likely

Detailed Forecast

This Afternoon
Mostly sunny, with a high near 88. South wind around 10 mph, with gusts as high as 20 mph.
Tonight
Increasing clouds, with a low around 68. South southeast wind around 10 mph, with gusts as high as 20 mph.
Friday
Cloudy, then gradually becoming mostly sunny, with a high near 89. South wind 10 to 15 mph, with gusts as high as 30 mph.
Friday Night
Mostly cloudy, with a low around 67. South southeast wind 5 to 15 mph, with gusts as high as 30 mph.
Saturday
A 50 percent chance of showers and thunderstorms, mainly after 1pm. Cloudy, with a high near 77. South southeast wind 5 to 15 mph becoming north in the afternoon. Winds could gust as high as 25 mph.
Saturday Night
Showers likely and possibly a thunderstorm before 1am, then a chance of showers. Cloudy, with a low around 54. North northeast wind around 15 mph, with gusts as high as 30 mph. Chance of precipitation is 60%.
Sunday
A 20 percent chance of showers. Mostly cloudy, with a high near 69. North northeast wind 10 to 15 mph, with gusts as high as 25 mph.
Sunday Night
A 30 percent chance of showers, mainly after 1am. Cloudy, with a low around 54. East northeast wind 5 to 10 mph.
Monday
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1pm. Cloudy, with a high near 65. East northeast wind 5 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 60%.
Monday Night
A 30 percent chance of showers and thunderstorms, mainly before 1am. Cloudy, with a low around 58.
Tuesday
A 30 percent chance of showers and thunderstorms. Cloudy, with a high near 75.
Tuesday Night
Mostly cloudy, with a low around 64.
Wednesday
A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 82.
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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:
12:16 pm CDT Apr 16, 2026
Forecast Valid:
12pm CDT Apr 16, 2026-6pm CDT Apr 22, 2026
 
Forecast Discussion
 
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Additional Resources

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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