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.

Fair and Breezy

77°F

25°C

Humidity 74%
Wind Speed S 22 mph
Barometer 29.84 in (1009.8 mb)
Dewpoint 68°F (20°C)
Visibility 10.00 mi
Heat Index79°F (26°C)
Last update 17 Apr 8:56 pm CDT
Extended Forecast for

San Marcos TX

  • Tonight

    Tonight: Mostly cloudy, with a low around 66. South wind 5 to 15 mph, with gusts as high as 25 mph.

    Low: 66 °F

    Mostly Cloudy

  • Saturday

    Saturday: A 50 percent chance of showers and thunderstorms, mainly after 1pm. Cloudy, with a temperature rising to near 71 by 9am, then falling to around 61 during the remainder of the day. South southwest wind 5 to 10 mph becoming north 10 to 15 mph in the afternoon. Winds could gust as high as 30 mph. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    High: 71 °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 and thunderstorms between 1am and 4am, then a chance of showers after 4am. Cloudy, with a low around 54. North northeast wind 15 to 20 mph, with gusts as high as 35 mph. Chance of precipitation is 70%. New rainfall amounts between a quarter and half of an inch possible.

    Low: 54 °F

    Showers
    Likely

  • 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: Mostly cloudy, with a low around 55. East northeast wind around 5 mph becoming calm in the evening.

    Low: 55 °F

    Mostly Cloudy

  • Monday

    Monday: A 50 percent chance of showers and thunderstorms. Cloudy, with a high near 67. East wind around 5 mph.

    High: 67 °F

    Chance
    Showers then
    Chance
    T-storms

  • Monday Night

    Monday Night: A 40 percent chance of showers and thunderstorms. Cloudy, with a low around 58. East wind around 5 mph becoming calm in the evening.

    Low: 58 °F

    Chance
    T-storms

  • Tuesday

    Tuesday: A 50 percent chance of showers and thunderstorms. Cloudy, with a high near 71. East southeast wind 5 to 10 mph.

    High: 71 °F

    Chance
    T-storms

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 64. Southeast wind 5 to 10 mph.

    Low: 64 °F

    Mostly Cloudy

Detailed Forecast

Tonight
Mostly cloudy, with a low around 66. South wind 5 to 15 mph, with gusts as high as 25 mph.
Saturday
A 50 percent chance of showers and thunderstorms, mainly after 1pm. Cloudy, with a temperature rising to near 71 by 9am, then falling to around 61 during the remainder of the day. South southwest wind 5 to 10 mph becoming north 10 to 15 mph in the afternoon. Winds could gust as high as 30 mph. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Saturday Night
Showers likely and possibly a thunderstorm before 1am, then a chance of showers and thunderstorms between 1am and 4am, then a chance of showers after 4am. Cloudy, with a low around 54. North northeast wind 15 to 20 mph, with gusts as high as 35 mph. Chance of precipitation is 70%. New rainfall amounts between a quarter and half of an inch possible.
Sunday
Partly sunny, with a high near 72. North northeast wind 10 to 15 mph, with gusts as high as 25 mph.
Sunday Night
Mostly cloudy, with a low around 55. East northeast wind around 5 mph becoming calm in the evening.
Monday
A 50 percent chance of showers and thunderstorms. Cloudy, with a high near 67. East wind around 5 mph.
Monday Night
A 40 percent chance of showers and thunderstorms. Cloudy, with a low around 58. East wind around 5 mph becoming calm in the evening.
Tuesday
A 50 percent chance of showers and thunderstorms. Cloudy, with a high near 71. East southeast wind 5 to 10 mph.
Tuesday Night
Mostly cloudy, with a low around 64. 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.
Wednesday Night
Mostly cloudy, with a low around 66.
Thursday
Mostly cloudy, with a high near 84.
Thursday Night
Mostly cloudy, with a low around 68.
Friday
A 30 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 84.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
San Marcos TX
 29.88°N 97.94°W (Elev. 577 ft)
Last Update:
6:44 pm CDT Apr 17, 2026
Forecast Valid:
9pm CDT Apr 17, 2026-6pm CDT Apr 24, 2026
 
Forecast Discussion
 
Get as KML Get as XML

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