Current conditions at

San Marcos, San Marcos Municipal Airport (KHYI)

Lat: 29.89° N Lon: 97.86° W Elev: 597 ft.

A Few Clouds

81°F

27°C

Humidity 88%
Wind Speed S 5 mph
Barometer 30.03 in (1016.1 mb)
Dewpoint 77°F (25°C)
Visibility 10.00 mi
Heat Index88°F (31°C)
Last update 31 Aug 8:56 am CDT
Detailed forecast for

Hays County

Today
Partly cloudy this morning, then clearing. Highs in the upper 90s. South winds 5 to 10 mph.
Tonight
Mostly clear. Lows in the mid 70s. Southeast winds 5 to 10 mph, becoming southwest after midnight.
Tuesday
Mostly sunny. Highs in the upper 90s. Southwest winds around 5 mph, becoming southeast around 5 mph in the afternoon.
Tuesday Night
Partly cloudy. Lows in the mid 70s. South winds around 5 mph.
Wednesday
Mostly sunny. Highs in the upper 90s. South winds around 5 mph.
Wednesday Night Through Friday
Partly cloudy with a slight chance of showers and thunderstorms. Lows in the mid 70s. Highs in the upper 90s. Highest heat index readings up to 105.
Friday Night
Partly cloudy with a slight chance of showers. Lows in the mid 70s.
Saturday
Partly cloudy in the morning, then clearing. A slight chance of showers. A slight chance of thunderstorms in the afternoon. Highs in the upper 90s. Highest heat index readings up to 105.
Saturday Night
Partly cloudy in the evening, then becoming mostly clear. Lows in the mid 70s.
Sunday
Mostly sunny with a slight chance of showers. A slight chance of thunderstorms in the afternoon. Highs in the upper 90s. Highest heat index readings up to 105.



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424 AM CDT Mon Aug 31 2026
 
 

Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database