Powerful Winter Storm from the Upper Midwest into the Northeast; Severe Thunderstorms in the Midwest and Ohio Valley

A rapidly-intensifying storm is expected to bring heavy snow, blizzard conditions, and icing from the Upper Midwest through the Great Lakes and Northeast. Scattered severe thunderstorms may produce severe/damaging wind gusts and a couple of tornadoes across parts of the Midwest and lower Ohio Valley through the evening. Arctic air will expand across the central and southern U.S.. Read More >

Current conditions at

SJSU - Mount Diablo Summit Museum Rooftop (SJS02)

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

NA

48°F

9°C

Humidity 24%
Wind Speed NE 5 MPH
Barometer NA
Dewpoint 13°F (-11°C)
Visibility NA
Wind Chill46°F (8°C)
Last update 29 Dec 04:20 AM PST
Extended Forecast for

4 Miles SSE Clayton CA

Cold Weather Advisory until December 29, 09:00am
Click here for hazard details and duration
Cold Weather Advisory
  •  
    Cold Weather Advisory until December 29, 09:00am

    NOW until 9:00am Mon

    Cold Weather Advisory

  • Overnight

    Low: 40 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 52. Northeast wind 6 to 9 mph.

    High: 52 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 42. East wind around 6 mph.

    Low: 42 °F

    Mostly Clear

  • Tuesday

    Tuesday: Mostly sunny, with a high near 48. East northeast wind around 9 mph.

    High: 48 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 42. East northeast wind around 7 mph.

    Low: 42 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: A 30 percent chance of rain after 10am.  Mostly cloudy, with a high near 47. New precipitation amounts of less than a tenth of an inch possible.

    High: 47 °F

    Chance Rain

  • Wednesday Night

    Wednesday Night: Rain likely, mainly after 10pm.  Mostly cloudy, with a low around 44. Chance of precipitation is 60%.

    Low: 44 °F

    Rain Likely

  • New Year's Day

    New Year's Day: Rain likely.  Mostly cloudy, with a high near 51.

    High: 51 °F

    Rain Likely

Detailed Forecast

Overnight
Mostly clear, with a low around 40. Northeast wind around 9 mph.
Monday
Sunny, with a high near 52. Northeast wind 6 to 9 mph.
Monday Night
Mostly clear, with a low around 42. East wind around 6 mph.
Tuesday
Mostly sunny, with a high near 48. East northeast wind around 9 mph.
Tuesday Night
Mostly cloudy, with a low around 42. East northeast wind around 7 mph.
Wednesday
A 30 percent chance of rain after 10am. Mostly cloudy, with a high near 47. New precipitation amounts of less than a tenth of an inch possible.
Wednesday Night
Rain likely, mainly after 10pm. Mostly cloudy, with a low around 44. Chance of precipitation is 60%.
New Year's Day
Rain likely. Mostly cloudy, with a high near 51.
Thursday Night
Rain likely. Mostly cloudy, with a low around 48.
Friday
Rain likely. Mostly cloudy, with a high near 52.
Friday Night
Rain likely. Mostly cloudy, with a low around 47.
Saturday
Rain likely. Mostly cloudy, with a high near 52.
Saturday Night
Rain likely. Mostly cloudy, with a low around 46.
Sunday
Rain likely. Partly sunny, with a high near 51.
Basemap Options
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ABOUT THIS FORECAST

 
Point Forecast:
4 Miles SSE Clayton CA
 37.87°N 121.92°W (Elev. 2818 ft)
12:27 am PST Dec 29, 2025
4am PST Dec 29, 2025-6pm PST Jan 4, 2026
 
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Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database