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.

Thunderstorm and Breezy

49°F

9°C

Humidity 93%
Wind Speed NE 21 G 25 mph
Barometer 30.29 in (1025.3 mb)
Dewpoint 47°F (8°C)
Visibility 10.00 mi
Wind Chill42°F (6°C)
Last update 19 Apr 12:56 am CDT
Extended Forecast for

San Marcos Municipal Airport TX

  • Overnight

    Overnight: A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 52. North northeast wind around 15 mph, with gusts as high as 25 mph.

    Low: 52 °F

    Chance
    T-storms

  • Sunday

    Sunday: Partly sunny, with a high near 73. East northeast wind 10 to 15 mph, with gusts as high as 25 mph.

    High: 73 °F

    Partly Sunny

  • Sunday Night

    Sunday Night: A 30 percent chance of showers, mainly after 4am. Mostly cloudy, with a low around 54. East wind around 5 mph becoming calm in the evening.

    Low: 54 °F

    Mostly Cloudy
    then Chance
    Showers

  • Monday

    Monday: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 7am. Cloudy, with a high near 67. East northeast wind 5 to 10 mph. Chance of precipitation is 60%.

    High: 67 °F

    Showers
    Likely

  • Monday Night

    Monday Night: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 57. East wind around 5 mph becoming calm in the evening. Chance of precipitation is 60%.

    Low: 57 °F

    Showers
    Likely

  • Tuesday

    Tuesday: Showers and possibly a thunderstorm. High near 70. East wind 5 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 80%.

    High: 70 °F

    Showers

  • Tuesday Night

    Tuesday Night: A 30 percent chance of showers and thunderstorms, mainly before 1am. Cloudy, with a low around 63. Southeast wind 5 to 10 mph.

    Low: 63 °F

    Chance
    Showers

  • Wednesday

    Wednesday: A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 80. Southeast wind 5 to 10 mph.

    High: 80 °F

    Chance
    T-storms

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 66. South southeast wind around 10 mph.

    Low: 66 °F

    Mostly Cloudy

Detailed Forecast

Overnight
A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 52. North northeast wind around 15 mph, with gusts as high as 25 mph.
Sunday
Partly sunny, with a high near 73. East northeast wind 10 to 15 mph, with gusts as high as 25 mph.
Sunday Night
A 30 percent chance of showers, mainly after 4am. Mostly cloudy, with a low around 54. East wind around 5 mph becoming calm in the evening.
Monday
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 7am. Cloudy, with a high near 67. East northeast wind 5 to 10 mph. Chance of precipitation is 60%.
Monday Night
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 57. East wind around 5 mph becoming calm in the evening. Chance of precipitation is 60%.
Tuesday
Showers and possibly a thunderstorm. High near 70. East wind 5 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 80%.
Tuesday Night
A 30 percent chance of showers and thunderstorms, mainly before 1am. Cloudy, with a low around 63. Southeast wind 5 to 10 mph.
Wednesday
A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 80. Southeast wind 5 to 10 mph.
Wednesday Night
Mostly cloudy, with a low around 66. South southeast wind around 10 mph.
Thursday
Mostly cloudy, with a high near 84.
Thursday Night
Mostly cloudy, with a low around 69.
Friday
A 30 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 86.
Friday Night
Partly cloudy, with a low around 64.
Saturday
A 20 percent chance of showers and thunderstorms. Partly sunny, with a high near 85.
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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:
1:24 am CDT Apr 19, 2026
Forecast Valid:
1am CDT Apr 19, 2026-6pm CDT Apr 25, 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