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

41°F

5°C

Humidity 99%
Wind Speed WNW 8 MPH
Barometer NA
Dewpoint 41°F (5°C)
Visibility NA
Wind Chill36°F (2°C)
Last update 07 Jan 03:35 PM PST
Extended Forecast for

4 Miles SSE 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 36. West wind 14 to 18 mph, with gusts as high as 32 mph.

    Low: 36 °F

    Partly Cloudy

  • Thursday

    Thursday: Sunny, with a high near 46. North northwest wind 10 to 13 mph, with gusts as high as 25 mph.

    High: 46 °F

    Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 34. North northwest wind around 9 mph, with gusts as high as 18 mph.

    Low: 34 °F

    Mostly Clear

  • Friday

    Friday: Sunny, with a high near 46. Northeast wind around 9 mph.

    High: 46 °F

    Sunny

  • Friday Night

    Friday Night: Areas of frost after 3am. Otherwise, mostly clear, with a low around 34. East northeast wind around 6 mph.

    Low: 34 °F

    Clear then
    Areas Frost

  • Saturday

    Saturday: Mostly sunny, with a high near 48.

    High: 48 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: Mostly cloudy, with a low around 37.

    Low: 37 °F

    Mostly Cloudy

  • Sunday

    Sunday: Partly sunny, with a high near 50.

    High: 50 °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 36. West wind 14 to 18 mph, with gusts as high as 32 mph.
Thursday
Sunny, with a high near 46. North northwest wind 10 to 13 mph, with gusts as high as 25 mph.
Thursday Night
Mostly clear, with a low around 34. North northwest wind around 9 mph, with gusts as high as 18 mph.
Friday
Sunny, with a high near 46. Northeast wind around 9 mph.
Friday Night
Areas of frost after 3am. Otherwise, mostly clear, with a low around 34. East northeast wind around 6 mph.
Saturday
Mostly sunny, with a high near 48.
Saturday Night
Mostly cloudy, with a low around 37.
Sunday
Partly sunny, with a high near 50.
Sunday Night
Partly cloudy, with a low around 39.
Monday
Sunny, with a high near 52.
Monday Night
Mostly clear, with a low around 41.
Tuesday
Mostly sunny, with a high near 55.
Tuesday Night
Mostly clear, with a low around 42.
Wednesday
Sunny, with a high near 56.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
4 Miles SSE Clayton CA
 37.9°N 121.9°W (Elev. 1814 ft)
Last Update:
12:26 pm PST Jan 7, 2026
Forecast Valid:
3pm PST Jan 7, 2026-6pm PST Jan 14, 2026
 
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