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.

Partly Cloudy

43°F

6°C

Humidity 43%
Wind Speed N 7 mph
Barometer 30.38 in (1028.6 mb)
Dewpoint 22°F (-6°C)
Visibility 10.00 mi
Wind Chill39°F (4°C)
Last update 20 Jan 4:56 am CST
Extended Forecast for

San Marcos TX

  • Today

    Today: Mostly cloudy, with a high near 60. North wind around 5 mph becoming east southeast in the afternoon.

    High: 60 °F

    Mostly Cloudy

  • Tonight

    Tonight: A 30 percent chance of showers, mainly after midnight.  Patchy fog between 3am and 5am.  Otherwise, cloudy, with a low around 52. East southeast wind around 5 mph.

    Low: 52 °F

    Chance
    Showers and
    Patchy Fog

  • Wednesday

    Wednesday: A 30 percent chance of showers.  Cloudy, then gradually becoming mostly sunny, with a high near 69. South wind around 5 mph becoming east in the afternoon.

    High: 69 °F

    Chance
    Showers

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 55. East northeast wind around 5 mph becoming calm.

    Low: 55 °F

    Mostly Cloudy

  • Thursday

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

    High: 71 °F

    Partly Sunny

  • Thursday Night

    Thursday Night: Mostly cloudy, with a low around 56. East southeast wind around 5 mph.

    Low: 56 °F

    Mostly Cloudy

  • Friday

    Friday: A 40 percent chance of showers, mainly after noon.  Cloudy, with a high near 68. East southeast wind 5 to 10 mph, with gusts as high as 20 mph.

    High: 68 °F

    Chance
    Showers

  • Friday Night

    Friday Night: Showers likely.  Cloudy, with a low around 37. North northeast wind 10 to 15 mph, with gusts as high as 20 mph.  Chance of precipitation is 70%.

    Low: 37 °F

    Showers
    Likely

  • Saturday

    Saturday: Showers likely, mainly before noon.  Cloudy, with a high near 40. North wind around 15 mph, with gusts as high as 30 mph.  Chance of precipitation is 70%.

    High: 40 °F

    Showers
    Likely

Detailed Forecast

Today
Mostly cloudy, with a high near 60. North wind around 5 mph becoming east southeast in the afternoon.
Tonight
A 30 percent chance of showers, mainly after midnight. Patchy fog between 3am and 5am. Otherwise, cloudy, with a low around 52. East southeast wind around 5 mph.
Wednesday
A 30 percent chance of showers. Cloudy, then gradually becoming mostly sunny, with a high near 69. South wind around 5 mph becoming east in the afternoon.
Wednesday Night
Mostly cloudy, with a low around 55. East northeast wind around 5 mph becoming calm.
Thursday
Partly sunny, with a high near 71. North wind around 5 mph becoming southeast in the afternoon.
Thursday Night
Mostly cloudy, with a low around 56. East southeast wind around 5 mph.
Friday
A 40 percent chance of showers, mainly after noon. Cloudy, with a high near 68. East southeast wind 5 to 10 mph, with gusts as high as 20 mph.
Friday Night
Showers likely. Cloudy, with a low around 37. North northeast wind 10 to 15 mph, with gusts as high as 20 mph. Chance of precipitation is 70%.
Saturday
Showers likely, mainly before noon. Cloudy, with a high near 40. North wind around 15 mph, with gusts as high as 30 mph. Chance of precipitation is 70%.
Saturday Night
A chance of freezing rain. Mostly cloudy, with a low around 24. Chance of precipitation is 40%.
Sunday
Partly sunny, with a high near 39.
Sunday Night
Partly cloudy, with a low around 24.
Monday
Mostly sunny, with a high near 45.
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ABOUT THIS FORECAST

 
Point Forecast:
San Marcos TX
 29.88°N 97.94°W (Elev. 577 ft)
4:32 am CST Jan 20, 2026
5am CST Jan 20, 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