Tracking Late December Winter Storm Expected to Impact the Northern Plains through the Northeast U.S.

A winter storm system will rapidly intensify over the Midwest on Sunday and track through the Great Lakes on Monday. Periods of heavy snow are anticipated across the Upper Great Lakes late Sunday and continuing into Monday. At least 1/10 inch of ice accumulation is expected from a wintry mix across much of the interior Northeast U.S. starting Sunday afternoon. Read More >

Current conditions at

SJSU - Mount Diablo Summit Museum Rooftop (SJS02)

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

NA

36°F

2°C

Humidity 56%
Wind Speed NNW 19 MPH
Barometer NA
Dewpoint 22°F (-6°C)
Visibility NA
Wind Chill26°F (-3°C)
Last update 28 Dec 06:40 AM PST
Extended Forecast for

Clayton CA

  • Today

    Today: Sunny, with a high near 49. Calm wind becoming north northeast around 6 mph in the morning.

    High: 49 °F

    Sunny

  • Tonight

    Tonight: Partly cloudy, with a low around 38. East northeast wind 3 to 6 mph.

    Low: 38 °F

    Partly Cloudy

  • Monday

    Monday: Sunny, with a high near 50. Northeast wind around 9 mph.

    High: 50 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 37. East northeast wind 3 to 5 mph.

    Low: 37 °F

    Mostly Clear

  • Tuesday

    Tuesday: Mostly sunny, with a high near 50. East northeast wind 7 to 9 mph.

    High: 50 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 39.

    Low: 39 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: A 10 percent chance of rain after 4pm.  Partly sunny, with a high near 49.

    High: 49 °F

    Partly Sunny
    then Slight
    Chance Rain

  • Wednesday Night

    Wednesday Night: A chance of rain, mainly after 10pm.  Mostly cloudy, with a low around 44.

    Low: 44 °F

    Chance Rain

  • New Year's Day

    New Year's Day: Rain likely, mainly between 10am and 4pm.  Mostly cloudy, with a high near 49.

    High: 49 °F

    Rain Likely

Detailed Forecast

Today
Sunny, with a high near 49. Calm wind becoming north northeast around 6 mph in the morning.
Tonight
Partly cloudy, with a low around 38. East northeast wind 3 to 6 mph.
Monday
Sunny, with a high near 50. Northeast wind around 9 mph.
Monday Night
Mostly clear, with a low around 37. East northeast wind 3 to 5 mph.
Tuesday
Mostly sunny, with a high near 50. East northeast wind 7 to 9 mph.
Tuesday Night
Mostly cloudy, with a low around 39.
Wednesday
A 10 percent chance of rain after 4pm. Partly sunny, with a high near 49.
Wednesday Night
A chance of rain, mainly after 10pm. Mostly cloudy, with a low around 44.
New Year's Day
Rain likely, mainly between 10am and 4pm. Mostly cloudy, with a high near 49.
Thursday Night
Rain likely, mainly after 10pm. Cloudy, with a low around 47.
Friday
Rain likely. Mostly cloudy, with a high near 52.
Friday Night
A chance of rain. Mostly cloudy, with a low around 48.
Saturday
A chance of rain. Mostly cloudy, with a high near 53.
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ABOUT THIS FORECAST

 
Point Forecast:
Clayton CA
 37.91°N 121.96°W (Elev. 1299 ft)
6:40 am PST Dec 28, 2025
6am PST Dec 28, 2025-6pm PST Jan 3, 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