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 100%
Wind Speed SE 6 mph
Barometer 30.16 in (1020.9 mb)
Dewpoint 59°F (15°C)
Visibility 10.00 mi
Last update 21 Apr 3:56 am CDT
Extended Forecast for

San Marcos TX

  • Overnight

    Overnight: Showers and possibly a thunderstorm. Low around 59. East wind around 5 mph. Chance of precipitation is 80%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    Low: 59 °F

    Showers

  • Tuesday

    Tuesday: Showers and possibly a thunderstorm. High near 69. 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: 69 °F

    Showers

  • Tuesday Night

    Tuesday Night: A 30 percent chance of showers and thunderstorms, mainly before 1am. Cloudy, with a low around 64. East wind 5 to 10 mph.

    Low: 64 °F

    Chance
    T-storms then
    Chance
    Showers

  • Wednesday

    Wednesday: A 50 percent chance of showers and thunderstorms, mainly after 1pm. Mostly cloudy, with a high near 80. South southeast wind 5 to 10 mph.

    High: 80 °F

    Slight Chance
    T-storms then
    Chance
    T-storms

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 67. South wind 5 to 10 mph.

    Low: 67 °F

    Mostly Cloudy

  • Thursday

    Thursday: Mostly cloudy, with a high near 83. South wind 5 to 10 mph, with gusts as high as 20 mph.

    High: 83 °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 86. South wind 5 to 10 mph.

    High: 86 °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

Overnight
Showers and possibly a thunderstorm. Low around 59. East wind around 5 mph. Chance of precipitation is 80%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Tuesday
Showers and possibly a thunderstorm. High near 69. 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 30 percent chance of showers and thunderstorms, mainly before 1am. Cloudy, with a low around 64. East wind 5 to 10 mph.
Wednesday
A 50 percent chance of showers and thunderstorms, mainly after 1pm. Mostly cloudy, with a high near 80. South southeast wind 5 to 10 mph.
Wednesday Night
Mostly cloudy, with a low around 67. South wind 5 to 10 mph.
Thursday
Mostly cloudy, with a high near 83. 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 86. South 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 86.
Saturday Night
Mostly cloudy, with a low around 69.
Sunday
Mostly cloudy, with a high near 88.
Sunday Night
A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 70.
Monday
A 20 percent chance of showers and thunderstorms. Partly sunny, with a high near 91.
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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 21, 2026
Forecast Valid:
4am CDT Apr 21, 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