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

Heavy Snow in the Cascades and Northern Rockies; Wintry Mix in the Northeast; High Winds in Southern California

Two more cold fronts will pass through the Northwest U.S. this week with heavy mountain snow continuing across the Cascades, and northern Rockies. A quick moving storm system will bring mixed precipitation including some freezing rain across the Northeast U.S. today. High winds could blow down trees and power lines in the mountains of southern California this evening through Thursday. Read More >

Hazardous Weather Conditions

Current conditions at

SJSU - Mount Diablo Summit Museum Rooftop (SJS02)

Lat: 37.881699°NLon: 121.914173°WElev: 3904.0ft.

NA

39°F

4°C

Humidity 100%
Wind Speed W 12 MPH
Barometer NA
Dewpoint 39°F (4°C)
Visibility NA
Wind Chill32°F (0°C)
Last update 07 Jan 04:50 PM PST
Extended Forecast for

2 Miles S Clayton CA

Extreme Cold Watch January 9, 01:00am until January 9, 09:00am
Click here for hazard details and duration
Extreme Cold Watch

  • Tonight

    Tonight: Partly cloudy, with a low around 40. West wind 11 to 15 mph, with gusts as high as 30 mph.

    Low: 40 °F

    Partly Cloudy

  • Thursday

    Thursday: Sunny, with a high near 52. West wind 10 to 13 mph becoming north in the morning. Winds could gust as high as 24 mph.

    High: 52 °F

    Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 37. North wind around 8 mph.

    Low: 37 °F

    Mostly Clear

  • Friday

    Friday: Sunny, with a high near 50. Northeast wind around 9 mph, with gusts as high as 18 mph.

    High: 50 °F

    Sunny

  • Friday Night

    Friday Night: Areas of frost after 5am. Otherwise, mostly clear, with a low around 35. East northeast wind around 5 mph.

    Low: 35 °F

    Mostly Clear
    then Areas
    Frost

  • Saturday

    Saturday: Areas of frost before 8am. Otherwise, mostly sunny, with a high near 52.

    High: 52 °F

    Areas Frost
    then Mostly
    Sunny

  • Saturday Night

    Saturday Night: Mostly cloudy, with a low around 38.

    Low: 38 °F

    Mostly Cloudy

  • Sunday

    Sunday: Partly sunny, with a high near 54.

    High: 54 °F

    Partly Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 39.

    Low: 39 °F

    Partly Cloudy

Detailed Forecast

Tonight
Partly cloudy, with a low around 40. West wind 11 to 15 mph, with gusts as high as 30 mph.
Thursday
Sunny, with a high near 52. West wind 10 to 13 mph becoming north in the morning. Winds could gust as high as 24 mph.
Thursday Night
Mostly clear, with a low around 37. North wind around 8 mph.
Friday
Sunny, with a high near 50. Northeast wind around 9 mph, with gusts as high as 18 mph.
Friday Night
Areas of frost after 5am. Otherwise, mostly clear, with a low around 35. East northeast wind around 5 mph.
Saturday
Areas of frost before 8am. Otherwise, mostly sunny, with a high near 52.
Saturday Night
Mostly cloudy, with a low around 38.
Sunday
Partly sunny, with a high near 54.
Sunday Night
Partly cloudy, with a low around 39.
Monday
Sunny, with a high near 56.
Monday Night
Mostly clear, with a low around 40.
Tuesday
Mostly sunny, with a high near 58.
Tuesday Night
Mostly clear, with a low around 42.
Wednesday
Sunny, with a high near 59.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
2 Miles S Clayton CA
 37.92°N 121.93°W (Elev. 600 ft)
Last Update:
12:26 pm PST Jan 7, 2026
Forecast Valid:
5pm PST Jan 7, 2026-6pm PST Jan 14, 2026
 
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Additional Resources

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