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 51. South southeast wind around 5 mph.

    Low: 51 °F

    Chance
    Showers and
    Patchy Fog

  • Wednesday

    Wednesday: A 30 percent chance of showers.  Cloudy, then gradually becoming mostly sunny, with a high near 70. Calm wind becoming south southwest around 5 mph in the morning.

    High: 70 °F

    Chance
    Showers

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 53. East northeast wind around 5 mph becoming calm.

    Low: 53 °F

    Mostly Cloudy

  • Thursday

    Thursday: Partly sunny, with a high near 72. North wind around 5 mph becoming southeast in the afternoon.

    High: 72 °F

    Partly Sunny

  • Thursday Night

    Thursday Night: Mostly cloudy, with a low around 54. East southeast wind around 5 mph.

    Low: 54 °F

    Mostly Cloudy

  • Friday

    Friday: A 40 percent chance of showers.  Cloudy, with a high near 69. East southeast wind 5 to 10 mph, with gusts as high as 20 mph.

    High: 69 °F

    Chance
    Showers

  • Friday Night

    Friday Night: Showers.  Low around 36. North northeast wind around 10 mph, with gusts as high as 20 mph.  Chance of precipitation is 80%.

    Low: 36 °F

    Showers

  • Saturday

    Saturday: Rain showers likely before noon, then a chance of rain or freezing rain.  Cloudy, with a high near 39. North wind 10 to 15 mph, with gusts as high as 30 mph.  Chance of precipitation is 70%.

    High: 39 °F

    Showers
    Likely then
    Chance
    Rain/Freezing
    Rain

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 51. South southeast wind around 5 mph.
Wednesday
A 30 percent chance of showers. Cloudy, then gradually becoming mostly sunny, with a high near 70. Calm wind becoming south southwest around 5 mph in the morning.
Wednesday Night
Mostly cloudy, with a low around 53. East northeast wind around 5 mph becoming calm.
Thursday
Partly sunny, with a high near 72. North wind around 5 mph becoming southeast in the afternoon.
Thursday Night
Mostly cloudy, with a low around 54. East southeast wind around 5 mph.
Friday
A 40 percent chance of showers. Cloudy, with a high near 69. East southeast wind 5 to 10 mph, with gusts as high as 20 mph.
Friday Night
Showers. Low around 36. North northeast wind around 10 mph, with gusts as high as 20 mph. Chance of precipitation is 80%.
Saturday
Rain showers likely before noon, then a chance of rain or freezing rain. Cloudy, with a high near 39. North wind 10 to 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 22. Chance of precipitation is 40%.
Sunday
Partly sunny, with a high near 39.
Sunday Night
Partly cloudy, with a low around 23.
Monday
Mostly sunny, with a high near 45.
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ABOUT THIS FORECAST

 
Point Forecast:
San Marcos TX
 29.9°N 97.91°W (Elev. 640 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