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

44°F

7°C

Humidity 40%
Wind Speed SW 5 mph
Barometer 30.30 in (1025.9 mb)
Dewpoint 21°F (-6°C)
Visibility 10.00 mi
Wind Chill41°F (5°C)
Last update 19 Jan 8:56 am CST
Extended Forecast for

San Marcos TX

  • M.L.King Day

    M.L.King Day: Sunny, with a high near 66. Light and variable wind becoming south southeast 5 to 10 mph in the afternoon.

    High: 66 °F

    Sunny

  • Tonight

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

    Low: 42 °F

    Increasing
    Clouds

  • Tuesday

    Tuesday: Cloudy, with a high near 57. North northeast wind around 5 mph becoming east in the afternoon.

    High: 57 °F

    Cloudy

  • Tuesday Night

    Tuesday Night: A 50 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, mainly before noon.  Mostly cloudy, with a high near 65. South southeast wind around 5 mph.

    High: 65 °F

    Chance
    Showers

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 51. East southeast wind around 5 mph becoming north after midnight.

    Low: 51 °F

    Mostly Cloudy

  • Thursday

    Thursday: Partly sunny, with a high near 69. North wind around 5 mph becoming east in the afternoon.

    High: 69 °F

    Partly Sunny

  • Thursday Night

    Thursday Night: Mostly cloudy, with a low around 50. Southeast wind around 5 mph.

    Low: 50 °F

    Mostly Cloudy

  • Friday

    Friday: A 20 percent chance of showers after noon.  Mostly cloudy, with a high near 69. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.

    High: 69 °F

    Cloudy then
    Slight Chance
    Showers

Detailed Forecast

M.L.King Day
Sunny, with a high near 66. Light and variable wind becoming south southeast 5 to 10 mph in the afternoon.
Tonight
Increasing clouds, with a low around 42. East southeast wind around 5 mph becoming north northeast after midnight.
Tuesday
Cloudy, with a high near 57. North northeast wind around 5 mph becoming east in the afternoon.
Tuesday Night
A 50 percent chance of showers. Cloudy, with a low around 51. South southeast wind around 5 mph.
Wednesday
A 40 percent chance of showers, mainly before noon. Mostly cloudy, with a high near 65. South southeast wind around 5 mph.
Wednesday Night
Mostly cloudy, with a low around 51. East southeast wind around 5 mph becoming north after midnight.
Thursday
Partly sunny, with a high near 69. North wind around 5 mph becoming east in the afternoon.
Thursday Night
Mostly cloudy, with a low around 50. Southeast wind around 5 mph.
Friday
A 20 percent chance of showers after noon. Mostly cloudy, with a high near 69. South southeast wind 5 to 10 mph, with gusts as high as 20 mph.
Friday Night
A 40 percent chance of showers. Mostly cloudy, with a low around 39.
Saturday
A 40 percent chance of showers. Mostly cloudy, with a high near 46.
Saturday Night
Mostly cloudy, with a low around 30.
Sunday
A 20 percent chance of showers. Mostly cloudy, with a high near 42.
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ABOUT THIS FORECAST

 
Point Forecast:
San Marcos TX
 29.88°N 97.94°W (Elev. 577 ft)
5:42 am CST Jan 19, 2026
9am CST Jan 19, 2026-6pm CST Jan 25, 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