National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Hazardous Weather Conditions

Current conditions at

San Marcos, San Marcos Municipal Airport (KHYI)

Lat: 29.89°NLon: 97.86°WElev: 597ft.

Overcast

82°F

28°C

Humidity 63%
Wind Speed Vrbl 6 mph
Barometer 30.00 in (1014.9 mb)
Dewpoint 68°F (20°C)
Visibility 10.00 mi
Heat Index85°F (29°C)
Last update 18 Nov 12:56 pm CST
Extended Forecast for

San Marcos TX

Flood Watch November 20, 12:00am until November 21, 06:00am
Click here for hazard details and duration
Flood Watch

  • This Afternoon

    This Afternoon: Mostly sunny, with a high near 84. South wind 5 to 10 mph.

    High: 84 °F

    Mostly Sunny

  • Tonight

    Tonight: A slight chance of drizzle after midnight. Increasing clouds, with a low around 68. South southeast wind around 5 mph.

    Low: 68 °F

    Partly Cloudy
    then Slight
    Chance
    Drizzle

  • Wednesday

    Wednesday: A chance of drizzle before noon, then a chance of showers and thunderstorms after noon. Cloudy, then gradually becoming mostly sunny, with a high near 84. South southeast wind 5 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 30%.

    High: 84 °F

    Chance
    Showers

  • Wednesday Night

    Wednesday Night: A chance of showers and thunderstorms. Mostly cloudy, with a low around 69. South southeast wind 5 to 10 mph. Chance of precipitation is 40%.

    Low: 69 °F

    Chance
    Showers

  • Thursday

    Thursday: Showers likely, then showers and possibly a thunderstorm after noon. High near 80. South southeast wind around 10 mph, with gusts as high as 20 mph. Chance of precipitation is 80%.

    High: 80 °F

    Showers

  • Thursday Night

    Thursday Night: Showers likely and possibly a thunderstorm before midnight, then a chance of showers and thunderstorms after midnight. Mostly cloudy, with a low around 66. East southeast wind 5 to 10 mph becoming south after midnight. Chance of precipitation is 60%.

    Low: 66 °F

    Showers
    Likely

  • Friday

    Friday: A 50 percent chance of showers, mainly before noon. Partly sunny, with a high near 80. South wind around 5 mph becoming north in the afternoon.

    High: 80 °F

    Chance
    Showers then
    Slight Chance
    Showers

  • Friday Night

    Friday Night: A 20 percent chance of showers after midnight. Partly cloudy, with a low around 60. Calm wind becoming north around 5 mph after midnight.

    Low: 60 °F

    Partly Cloudy
    then Slight
    Chance
    Showers

  • Saturday

    Saturday: A 30 percent chance of showers, mainly after noon. Mostly sunny, with a high near 75. Northeast wind 5 to 10 mph.

    High: 75 °F

    Chance
    Showers

Detailed Forecast

This Afternoon
Mostly sunny, with a high near 84. South wind 5 to 10 mph.
Tonight
A slight chance of drizzle after midnight. Increasing clouds, with a low around 68. South southeast wind around 5 mph.
Wednesday
A chance of drizzle before noon, then a chance of showers and thunderstorms after noon. Cloudy, then gradually becoming mostly sunny, with a high near 84. South southeast wind 5 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 30%.
Wednesday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 69. South southeast wind 5 to 10 mph. Chance of precipitation is 40%.
Thursday
Showers likely, then showers and possibly a thunderstorm after noon. High near 80. South southeast wind around 10 mph, with gusts as high as 20 mph. Chance of precipitation is 80%.
Thursday Night
Showers likely and possibly a thunderstorm before midnight, then a chance of showers and thunderstorms after midnight. Mostly cloudy, with a low around 66. East southeast wind 5 to 10 mph becoming south after midnight. Chance of precipitation is 60%.
Friday
A 50 percent chance of showers, mainly before noon. Partly sunny, with a high near 80. South wind around 5 mph becoming north in the afternoon.
Friday Night
A 20 percent chance of showers after midnight. Partly cloudy, with a low around 60. Calm wind becoming north around 5 mph after midnight.
Saturday
A 30 percent chance of showers, mainly after noon. Mostly sunny, with a high near 75. Northeast wind 5 to 10 mph.
Saturday Night
A 30 percent chance of showers. Mostly cloudy, with a low around 59.
Sunday
A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 75.
Sunday Night
A 40 percent chance of showers. Mostly cloudy, with a low around 62.
Monday
A 50 percent chance of showers and thunderstorms. Partly sunny, with a high near 75.
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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:
12:44 pm CST Nov 18, 2025
Forecast Valid:
1pm CST Nov 18, 2025-6pm CST Nov 24, 2025
 
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