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

58°F

14°C

Humidity 97%
Wind Speed NE 9 mph
Barometer 30.24 in (1023.8 mb)
Dewpoint 57°F (14°C)
Visibility 10.00 mi
Last update 20 Apr 4:56 pm CDT
Extended Forecast for

San Marcos Municipal Airport TX

  • This Afternoon

    This Afternoon: Showers and possibly a thunderstorm. High near 62. East northeast wind around 10 mph. Chance of precipitation is 80%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    High: 62 °F

    Showers

  • Tonight

    Tonight: Showers and possibly a thunderstorm before 1am, then a chance of showers and thunderstorms between 1am and 4am, then showers likely and possibly a thunderstorm after 4am. Low around 58. East wind around 5 mph. Chance of precipitation is 80%. New rainfall amounts between a half and three quarters of an inch possible.

    Low: 58 °F

    Showers

  • Tuesday

    Tuesday: Showers and possibly a thunderstorm, mainly before 4pm, then a chance of showers and thunderstorms after 4pm. 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 40 percent chance of showers and thunderstorms. Cloudy, with a low around 63. Southeast wind 5 to 10 mph.

    Low: 63 °F

    Chance
    T-storms

  • Wednesday

    Wednesday: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1pm. Mostly cloudy, with a high near 80. Southeast wind 5 to 10 mph. Chance of precipitation is 60%.

    High: 80 °F

    Chance
    Showers then
    Showers
    Likely

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 65. Southeast wind 5 to 10 mph.

    Low: 65 °F

    Mostly Cloudy

  • Thursday

    Thursday: Mostly cloudy, with a high near 85. South wind 5 to 15 mph, with gusts as high as 20 mph.

    High: 85 °F

    Mostly Cloudy

  • Thursday Night

    Thursday Night: Mostly cloudy, with a low around 68. South southeast wind around 10 mph, with gusts as high as 20 mph.

    Low: 68 °F

    Mostly Cloudy

  • Friday

    Friday: A 20 percent chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 88. South southwest wind 5 to 10 mph.

    High: 88 °F

    Cloudy then
    Slight Chance
    T-storms

Detailed Forecast

This Afternoon
Showers and possibly a thunderstorm. High near 62. East northeast wind around 10 mph. Chance of precipitation is 80%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Tonight
Showers and possibly a thunderstorm before 1am, then a chance of showers and thunderstorms between 1am and 4am, then showers likely and possibly a thunderstorm after 4am. Low around 58. East wind around 5 mph. Chance of precipitation is 80%. New rainfall amounts between a half and three quarters of an inch possible.
Tuesday
Showers and possibly a thunderstorm, mainly before 4pm, then a chance of showers and thunderstorms after 4pm. 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 40 percent chance of showers and thunderstorms. Cloudy, with a low around 63. Southeast wind 5 to 10 mph.
Wednesday
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1pm. Mostly cloudy, with a high near 80. Southeast wind 5 to 10 mph. Chance of precipitation is 60%.
Wednesday Night
Mostly cloudy, with a low around 65. Southeast wind 5 to 10 mph.
Thursday
Mostly cloudy, with a high near 85. South wind 5 to 15 mph, with gusts as high as 20 mph.
Thursday Night
Mostly cloudy, with a low around 68. 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 88. South southwest wind 5 to 10 mph.
Friday Night
Partly cloudy, with a low around 68.
Saturday
A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 89.
Saturday Night
Mostly cloudy, with a low around 68.
Sunday
A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 88.
Sunday Night
Mostly cloudy, with a low around 69.
Monday
A slight chance of showers and thunderstorms. Mostly cloudy, with a high near 89.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
San Marcos Municipal Airport TX
 29.88°N 97.86°W (Elev. 600 ft)
Last Update:
2:46 pm CDT Apr 20, 2026
Forecast Valid:
5pm CDT Apr 20, 2026-6pm CDT Apr 27, 2026
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

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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