National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Rapid Warm-Up Forecast Across Much of the Lower 48 Today and Tuesday

Most of the U.S. starts the week calm and unseasonably warm. The Heartland will be warmest, with highs 25–30° above average. Only the Gulf Coast stays chilly. Rain today is limited to western Washington while lake effect snow continues east of Lake Ontario. Cooler air returns after Tuesday, bringing a wintry mix to the Midwest and Northeast by Wednesday. Read More >

Current conditions at

San Marcos, San Marcos Municipal Airport (KHYI)

Lat: 29.89°NLon: 97.86°WElev: 597ft.

Mostly Cloudy

50°F

10°C

Humidity 43%
Wind Speed N 5 mph
Barometer 30.50 in (1032.8 mb)
Dewpoint 28°F (-2°C)
Visibility 10.00 mi
Wind Chill48°F (9°C)
Last update 12 Jan 8:56 am CST
Extended Forecast for

4 Miles NNW San Marcos Municipal Airport TX

  • Today

    Today: Partly sunny, with a high near 63. North wind around 5 mph becoming east in the afternoon.

    High: 63 °F

    Partly Sunny

  • Tonight

    Tonight: A 20 percent chance of showers after midnight. Mostly cloudy, with a low around 45. East southeast wind around 5 mph becoming calm.

    Low: 45 °F

    Mostly Cloudy
    then Slight
    Chance
    Showers

  • Tuesday

    Tuesday: A 20 percent chance of showers before noon. Cloudy, then gradually becoming mostly sunny, with a high near 61. Southwest wind around 5 mph.

    High: 61 °F

    Slight Chance
    Showers then
    Partly Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 42. West southwest wind around 5 mph.

    Low: 42 °F

    Mostly Clear

  • Wednesday

    Wednesday: Sunny, with a high near 70. West wind 5 to 15 mph becoming north in the morning. Winds could gust as high as 25 mph.

    High: 70 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Clear, with a low around 36. North wind 10 to 15 mph, with gusts as high as 20 mph.

    Low: 36 °F

    Clear

  • Thursday

    Thursday: Sunny, with a high near 61. North wind 5 to 10 mph becoming south southeast in the afternoon.

    High: 61 °F

    Sunny

  • Thursday Night

    Thursday Night: Clear, with a low around 38. South southwest wind around 5 mph.

    Low: 38 °F

    Clear

  • Friday

    Friday: Sunny, with a high near 66. Southwest wind 5 to 10 mph becoming east northeast in the afternoon. Winds could gust as high as 20 mph.

    High: 66 °F

    Sunny

Detailed Forecast

Today
Partly sunny, with a high near 63. North wind around 5 mph becoming east in the afternoon.
Tonight
A 20 percent chance of showers after midnight. Mostly cloudy, with a low around 45. East southeast wind around 5 mph becoming calm.
Tuesday
A 20 percent chance of showers before noon. Cloudy, then gradually becoming mostly sunny, with a high near 61. Southwest wind around 5 mph.
Tuesday Night
Mostly clear, with a low around 42. West southwest wind around 5 mph.
Wednesday
Sunny, with a high near 70. West wind 5 to 15 mph becoming north in the morning. Winds could gust as high as 25 mph.
Wednesday Night
Clear, with a low around 36. North wind 10 to 15 mph, with gusts as high as 20 mph.
Thursday
Sunny, with a high near 61. North wind 5 to 10 mph becoming south southeast in the afternoon.
Thursday Night
Clear, with a low around 38. South southwest wind around 5 mph.
Friday
Sunny, with a high near 66. Southwest wind 5 to 10 mph becoming east northeast in the afternoon. Winds could gust as high as 20 mph.
Friday Night
Partly cloudy, with a low around 38.
Saturday
Sunny, with a high near 60.
Saturday Night
Mostly clear, with a low around 35.
Sunday
Sunny, with a high near 65.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
4 Miles NNW San Marcos Municipal Airport TX
 29.95°N 97.89°W (Elev. 646 ft)
Last Update:
8:32 am CST Jan 12, 2026
Forecast Valid:
9am CST Jan 12, 2026-6pm CST Jan 18, 2026
 
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