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

Atmospheric River Bringing Heavy Rain to Southern California and Heavy Snow to the Sierra Nevadas

A strong atmospheric river will continue heavy rain over southern California through Friday. The heaviest rainfall is ongoing today in the Los Angeles Basin. Flash and urban flooding is possible. A prolonged heavy snowfall has begun over the Sierra Nevada Mountains and will continue through Friday. Travel will become increasingly difficult over the passes due to snow and strong winds. Read More >

Current conditions at

San Marcos, San Marcos Municipal Airport (KHYI)

Lat: 29.89°NLon: 97.86°WElev: 597ft.

Overcast

67°F

19°C

Humidity 97%
Wind Speed SW 8 mph
Barometer 30.08 in (1018.0 mb)
Dewpoint 66°F (19°C)
Visibility 10.00 mi
Last update 26 Dec 1:56 am CST
Extended Forecast for

San Marcos TX

  • Overnight

    Overnight: Areas of fog. Otherwise, cloudy, with a low around 64. South southwest wind around 5 mph.

    Low: 64 °F

    Areas Fog

  • Friday

    Friday: Areas of fog before 9am. Otherwise, cloudy through mid morning, then gradual clearing, with a high near 83. South southwest wind 5 to 10 mph.

    High: 83 °F

    Areas Fog
    then Mostly
    Sunny

  • Friday Night

    Friday Night: Increasing clouds, with a low around 65. South southwest wind 5 to 10 mph.

    Low: 65 °F

    Increasing
    Clouds

  • Saturday

    Saturday: Cloudy, then gradually becoming mostly sunny, with a high near 80. South wind around 10 mph.

    High: 80 °F

    Decreasing
    Clouds

  • Saturday Night

    Saturday Night: Mostly cloudy, with a low around 66. South southeast wind around 10 mph.

    Low: 66 °F

    Mostly Cloudy

  • Sunday

    Sunday: Mostly cloudy, with a high near 80. South wind 5 to 10 mph.

    High: 80 °F

    Mostly Cloudy

  • Sunday Night

    Sunday Night: A chance of showers before midnight, then a chance of showers and thunderstorms between midnight and 3am, then a chance of showers after 3am. Mostly cloudy, with a low around 43. South wind 5 to 10 mph becoming north 15 to 20 mph after midnight. Winds could gust as high as 30 mph. Chance of precipitation is 40%.

    Low: 43 °F

    Chance
    Showers

  • Monday

    Monday: Mostly cloudy, with a high near 50. North wind 15 to 20 mph, with gusts as high as 35 mph.

    High: 50 °F

    Mostly Cloudy

  • Monday Night

    Monday Night: Mostly cloudy, with a low around 36. North wind 10 to 15 mph, with gusts as high as 25 mph.

    Low: 36 °F

    Mostly Cloudy

Detailed Forecast

Overnight
Areas of fog. Otherwise, cloudy, with a low around 64. South southwest wind around 5 mph.
Friday
Areas of fog before 9am. Otherwise, cloudy through mid morning, then gradual clearing, with a high near 83. South southwest wind 5 to 10 mph.
Friday Night
Increasing clouds, with a low around 65. South southwest wind 5 to 10 mph.
Saturday
Cloudy, then gradually becoming mostly sunny, with a high near 80. South wind around 10 mph.
Saturday Night
Mostly cloudy, with a low around 66. South southeast wind around 10 mph.
Sunday
Mostly cloudy, with a high near 80. South wind 5 to 10 mph.
Sunday Night
A chance of showers before midnight, then a chance of showers and thunderstorms between midnight and 3am, then a chance of showers after 3am. Mostly cloudy, with a low around 43. South wind 5 to 10 mph becoming north 15 to 20 mph after midnight. Winds could gust as high as 30 mph. Chance of precipitation is 40%.
Monday
Mostly cloudy, with a high near 50. North wind 15 to 20 mph, with gusts as high as 35 mph.
Monday Night
Mostly cloudy, with a low around 36. North wind 10 to 15 mph, with gusts as high as 25 mph.
Tuesday
Mostly cloudy, with a high near 53.
Tuesday Night
Mostly cloudy, with a low around 36.
Wednesday
Mostly sunny, with a high near 61.
Wednesday Night
Mostly cloudy, with a low around 40.
New Year's Day
Partly sunny, with a high near 67.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
San Marcos TX
 29.88°N 97.94°W (Elev. 577 ft)
Last Update:
12:46 am CST Dec 26, 2025
Forecast Valid:
2am CST Dec 26, 2025-6pm CST Jan 1, 2026
 
Forecast Discussion
 
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Additional Resources

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Hourly Weather Forecast

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation