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 98%
Wind Speed WNW 8 MPH
Barometer NA
Dewpoint 38°F (3°C)
Visibility NA
Wind Chill33°F (1°C)
Last update 07 Jan 11:50 AM PST
Extended Forecast for

3 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

  • This Afternoon

    This Afternoon: Mostly sunny, with a high near 49. West wind 10 to 13 mph, with gusts as high as 23 mph.

    High: 49 °F

    Mostly Sunny

  • Tonight

    Tonight: Mostly cloudy, then gradually becoming clear, with a low around 36. West wind 16 to 18 mph, with gusts as high as 32 mph.

    Low: 36 °F

    Decreasing
    Clouds

  • Thursday

    Thursday: Sunny, with a high near 45. North wind 11 to 14 mph, with gusts as high as 25 mph.

    High: 45 °F

    Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 34. North wind around 9 mph, with gusts as high as 20 mph.

    Low: 34 °F

    Mostly Clear

  • Friday

    Friday: Sunny, with a high near 46. Northeast wind around 9 mph, with gusts as high as 18 mph.

    High: 46 °F

    Sunny

  • Friday Night

    Friday Night: Mostly clear, with a low around 34.

    Low: 34 °F

    Mostly Clear

  • 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

Detailed Forecast

This Afternoon
Mostly sunny, with a high near 49. West wind 10 to 13 mph, with gusts as high as 23 mph.
Tonight
Mostly cloudy, then gradually becoming clear, with a low around 36. West wind 16 to 18 mph, with gusts as high as 32 mph.
Thursday
Sunny, with a high near 45. North wind 11 to 14 mph, with gusts as high as 25 mph.
Thursday Night
Mostly clear, with a low around 34. North wind around 9 mph, with gusts as high as 20 mph.
Friday
Sunny, with a high near 46. Northeast wind around 9 mph, with gusts as high as 18 mph.
Friday Night
Mostly clear, with a low around 34.
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
Sunny, with a high near 55.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
3 Miles S Clayton CA
 37.9°N 121.92°W (Elev. 1900 ft)
Last Update:
11:26 am PST Jan 7, 2026
Forecast Valid:
12pm PST Jan 7, 2026-6pm PST Jan 13, 2026
 
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