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 >

Hazardous Weather Conditions

Current conditions at

San Francisco, San Francisco International Airport (KSFO)

Lat: 37.61961°NLon: 122.36558°WElev: 10.0ft.

Clear

55°F

13°C

Humidity 66%
Wind Speed SW 24 MPH
Barometer 29.86 in (1011.18 mb)
Dewpoint 44°F (7°C)
Visibility 7.00 mi
Last update 26 Dec 01:20 AM PST
Extended Forecast for

Foster City CA

Flood Watch December 26, 01:33am until December 26, 10:00pm
Click here for hazard details and duration
Flood Watch
  •  
    Flood Watch December 26, 01:33am until December 26, 10:00pm

    NOW until 10:00pm Fri

    Flood Watch

  • Overnight

    Low: 51 °F

    Chance
    Showers

  • Friday

    Friday: Showers likely, with thunderstorms also possible after 4pm. Mostly cloudy, with a high near 59. South southeast wind 11 to 14 mph, with gusts as high as 23 mph. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

    High: 59 °F

    Showers
    Likely

  • Friday Night

    Friday Night: A chance of showers and thunderstorms. Mostly cloudy, with a low around 46. South southeast wind 7 to 9 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    Low: 46 °F

    Chance
    Showers

  • Saturday

    Saturday: A 20 percent chance of showers. Mostly sunny, with a high near 55. North northwest wind around 7 mph.

    High: 55 °F

    Slight Chance
    Showers

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 40. Northeast wind 3 to 6 mph.

    Low: 40 °F

    Mostly Clear

  • Sunday

    Sunday: Mostly sunny, with a high near 56.

    High: 56 °F

    Mostly Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 40.

    Low: 40 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 58.

    High: 58 °F

    Sunny

Detailed Forecast

Overnight
A 50 percent chance of showers. Mostly cloudy, with a low around 51. South wind around 14 mph, with gusts as high as 24 mph. New precipitation amounts of less than a tenth of an inch possible.
Friday
Showers likely, with thunderstorms also possible after 4pm. Mostly cloudy, with a high near 59. South southeast wind 11 to 14 mph, with gusts as high as 23 mph. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Friday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 46. South southeast wind 7 to 9 mph. Chance of precipitation is 50%. New precipitation amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Saturday
A 20 percent chance of showers. Mostly sunny, with a high near 55. North northwest wind around 7 mph.
Saturday Night
Mostly clear, with a low around 40. Northeast wind 3 to 6 mph.
Sunday
Mostly sunny, with a high near 56.
Sunday Night
Mostly clear, with a low around 40.
Monday
Sunny, with a high near 58.
Monday Night
Mostly clear, with a low around 40.
Tuesday
Sunny, with a high near 58.
Tuesday Night
Mostly clear, with a low around 41.
Wednesday
Mostly sunny, with a high near 59.
Wednesday Night
A slight chance of showers. Partly cloudy, with a low around 45.
New Year's Day
A chance of showers. Partly sunny, with a high near 58.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Foster City CA
 37.57°N 122.27°W (Elev. 3 ft)
Last Update:
12:27 am PST Dec 26, 2025
Forecast Valid:
1am PST Dec 26, 2025-6pm PST Jan 1, 2026
 
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Additional Resources

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Hourly Weather Forecast

National Digital Forecast Database

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation