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

83°F

28°C

Humidity 61%
Wind Speed NE 3 mph
Barometer 30.10 in
Dewpoint 68°F (20°C)
Visibility 10.00 mi
Heat Index86°F (30°C)
Last update 1 Aug 9:56 pm CDT
Extended Forecast for

San Marcos TX

  • Tonight

    Tonight: Partly cloudy, with a low around 76. Calm wind.

    Low: 76 °F

    Partly Cloudy

  • Saturday

    Saturday: A 40 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 96. Heat index values as high as 102. Calm wind.

    High: 96 °F

    Mostly Sunny
    then Chance
    T-storms

  • Saturday Night

    Saturday Night: A chance of showers and thunderstorms before 10pm, then a slight chance of showers between 10pm and 1am. Partly cloudy, with a low around 76. North northwest wind around 5 mph becoming calm. Chance of precipitation is 30%.

    Low: 76 °F

    Chance
    T-storms then
    Slight Chance
    Showers

  • Sunday

    Sunday: A slight chance of showers between 1pm and 4pm, then a slight chance of showers and thunderstorms after 4pm. Sunny, with a high near 97. Heat index values as high as 105. Calm wind becoming east southeast around 5 mph. Chance of precipitation is 20%.

    High: 97 °F

    Sunny then
    Slight Chance
    T-storms

  • Sunday Night

    Sunday Night: A slight chance of showers and thunderstorms before 10pm, then a slight chance of showers between 10pm and 1am. Mostly clear, with a low around 76. South southeast wind around 5 mph. Chance of precipitation is 20%.

    Low: 76 °F

    Slight Chance
    T-storms then
    Slight Chance
    Showers

  • Monday

    Monday: A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 95. Calm wind becoming east southeast around 5 mph in the afternoon.

    High: 95 °F

    Mostly Sunny
    then Slight
    Chance
    T-storms

  • Monday Night

    Monday Night: Partly cloudy, with a low around 75. East southeast wind around 5 mph becoming calm after midnight.

    Low: 75 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Sunny, with a high near 94. Calm wind becoming east southeast around 5 mph in the afternoon.

    High: 94 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 75. East southeast wind around 5 mph becoming south after midnight.

    Low: 75 °F

    Mostly Clear

Detailed Forecast

Tonight
Partly cloudy, with a low around 76. Calm wind.
Saturday
A 40 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 96. Heat index values as high as 102. Calm wind.
Saturday Night
A chance of showers and thunderstorms before 10pm, then a slight chance of showers between 10pm and 1am. Partly cloudy, with a low around 76. North northwest wind around 5 mph becoming calm. Chance of precipitation is 30%.
Sunday
A slight chance of showers between 1pm and 4pm, then a slight chance of showers and thunderstorms after 4pm. Sunny, with a high near 97. Heat index values as high as 105. Calm wind becoming east southeast around 5 mph. Chance of precipitation is 20%.
Sunday Night
A slight chance of showers and thunderstorms before 10pm, then a slight chance of showers between 10pm and 1am. Mostly clear, with a low around 76. South southeast wind around 5 mph. Chance of precipitation is 20%.
Monday
A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 95. Calm wind becoming east southeast around 5 mph in the afternoon.
Monday Night
Partly cloudy, with a low around 75. East southeast wind around 5 mph becoming calm after midnight.
Tuesday
Sunny, with a high near 94. Calm wind becoming east southeast around 5 mph in the afternoon.
Tuesday Night
Mostly clear, with a low around 75. East southeast wind around 5 mph becoming south after midnight.
Wednesday
Sunny, with a high near 95.
Wednesday Night
Mostly clear, with a low around 75.
Thursday
Sunny, with a high near 96.
Thursday Night
Mostly clear, with a low around 75.
Friday
Sunny, with a high near 96.
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:
6:42 pm CDT Aug 1, 2025
Forecast Valid:
10pm CDT Aug 1, 2025-6pm CDT Aug 8, 2025
 
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