Lake-effect Snow and Whiteout Conditions in the Great Lakes Region; Below-average Temperatures in the East

Heavy lake-effect and lake-enhanced snow will persist downwind of the Great Lakes and produce some whiteout conditions that could cause difficult travel conditions. A coastal low will produce moderate to heavy snow over parts of southern and eastern New England into the afternoon. Below average temperatures are expected across the eastern U.S., particularly with chilly morning temperatures. Read More >

Current conditions at

San Marcos, San Marcos Municipal Airport (KHYI)

Lat: 29.89°NLon: 97.86°WElev: 597ft.

Fair

68°F

20°C

Humidity 23%
Wind Speed S 10 mph
Barometer 30.19 in (1022.4 mb)
Dewpoint 29°F (-2°C)
Visibility 10.00 mi
Last update 19 Jan 3:56 pm CST
Extended Forecast for

San Marcos TX

  • Tonight

    Tonight: Increasing clouds, with a low around 42. Southeast wind around 5 mph becoming north after midnight.

    Low: 42 °F

    Increasing
    Clouds

  • Tuesday

    Tuesday: Cloudy, with a high near 59. North wind around 5 mph becoming east in the afternoon.

    High: 59 °F

    Cloudy

  • Tuesday Night

    Tuesday Night: A 40 percent chance of showers.  Cloudy, with a low around 51. South southeast wind around 5 mph.

    Low: 51 °F

    Chance
    Showers

  • Wednesday

    Wednesday: A 40 percent chance of showers.  Mostly cloudy, with a high near 68. South southeast wind around 5 mph.

    High: 68 °F

    Chance
    Showers

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 52. North wind around 5 mph.

    Low: 52 °F

    Mostly Cloudy

  • Thursday

    Thursday: Partly sunny, with a high near 71. North wind around 5 mph becoming east in the afternoon.

    High: 71 °F

    Partly Sunny

  • Thursday Night

    Thursday Night: Mostly cloudy, with a low around 53. Southeast wind around 5 mph.

    Low: 53 °F

    Mostly Cloudy

  • Friday

    Friday: A 30 percent chance of showers, mainly after noon.  Cloudy, with a high near 67. Southeast wind 5 to 10 mph, with gusts as high as 20 mph.

    High: 67 °F

    Chance
    Showers

  • Friday Night

    Friday Night: Showers likely, mainly after midnight.  Cloudy, with a low around 33. North wind 10 to 15 mph, with gusts as high as 20 mph.  Chance of precipitation is 60%.

    Low: 33 °F

    Showers
    Likely

Detailed Forecast

Tonight
Increasing clouds, with a low around 42. Southeast wind around 5 mph becoming north after midnight.
Tuesday
Cloudy, with a high near 59. North wind around 5 mph becoming east in the afternoon.
Tuesday Night
A 40 percent chance of showers. Cloudy, with a low around 51. South southeast wind around 5 mph.
Wednesday
A 40 percent chance of showers. Mostly cloudy, with a high near 68. South southeast wind around 5 mph.
Wednesday Night
Mostly cloudy, with a low around 52. North wind around 5 mph.
Thursday
Partly sunny, with a high near 71. North wind around 5 mph becoming east in the afternoon.
Thursday Night
Mostly cloudy, with a low around 53. Southeast wind around 5 mph.
Friday
A 30 percent chance of showers, mainly after noon. Cloudy, with a high near 67. Southeast wind 5 to 10 mph, with gusts as high as 20 mph.
Friday Night
Showers likely, mainly after midnight. Cloudy, with a low around 33. North wind 10 to 15 mph, with gusts as high as 20 mph. Chance of precipitation is 60%.
Saturday
Showers likely, mainly before noon. Mostly cloudy, with a high near 40. Chance of precipitation is 60%.
Saturday Night
A chance of rain or freezing rain. Mostly cloudy, with a low around 24. Chance of precipitation is 30%.
Sunday
Partly sunny, with a high near 38.
Sunday Night
Mostly cloudy, with a low around 24.
Monday
Partly sunny, with a high near 46.
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ABOUT THIS FORECAST

 
Point Forecast:
San Marcos TX
 29.88°N 97.94°W (Elev. 577 ft)
4:32 pm CST Jan 19, 2026
4pm CST Jan 19, 2026-6pm CST Jan 26, 2026
 
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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