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

38°F

3°C

Humidity 88%
Wind Speed N 6 MPH
Barometer NA
Dewpoint 35°F (2°C)
Visibility NA
Wind Chill33°F (1°C)
Last update 27 Dec 08:50 AM PST
Extended Forecast for

3 Miles NNE San Ramon CA

  • Today

    Today: Mostly sunny, with a high near 52. Calm wind becoming north northwest around 6 mph in the afternoon.

    High: 52 °F

    Mostly Sunny

  • Tonight

    Tonight: Areas of frost between 3am and 4am.  Otherwise, partly cloudy, with a low around 36. Calm wind.

    Low: 36 °F

    Mostly Clear
    then Areas
    Frost

  • Sunday

    Sunday: Patchy frost before 8am.  Otherwise, sunny, with a high near 52. Calm wind becoming north northeast around 5 mph in the afternoon.

    High: 52 °F

    Patchy Frost
    then Sunny

  • Sunday Night

    Sunday Night: Patchy frost after 3am.  Otherwise, mostly clear, with a low around 35. Calm wind.

    Low: 35 °F

    Mostly Clear
    then Patchy
    Frost

  • Monday

    Monday: Areas of frost before 9am.  Otherwise, sunny, with a high near 53. Calm wind becoming northeast around 5 mph in the morning.

    High: 53 °F

    Areas Frost
    then Sunny

  • Monday Night

    Monday Night: Areas of frost after 3am.  Otherwise, mostly clear, with a low around 34.

    Low: 34 °F

    Clear then
    Areas Frost

  • Tuesday

    Tuesday: Areas of frost before 9am.  Otherwise, mostly sunny, with a high near 55.

    High: 55 °F

    Areas Frost
    then Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 36.

    Low: 36 °F

    Mostly Clear

  • Wednesday

    Wednesday: A slight chance of rain after 4pm.  Patchy frost before 7am.  Otherwise, mostly sunny, with a high near 54.

    High: 54 °F

    Patchy Frost
    then Slight
    Chance Rain

Detailed Forecast

Today
Mostly sunny, with a high near 52. Calm wind becoming north northwest around 6 mph in the afternoon.
Tonight
Areas of frost between 3am and 4am. Otherwise, partly cloudy, with a low around 36. Calm wind.
Sunday
Patchy frost before 8am. Otherwise, sunny, with a high near 52. Calm wind becoming north northeast around 5 mph in the afternoon.
Sunday Night
Patchy frost after 3am. Otherwise, mostly clear, with a low around 35. Calm wind.
Monday
Areas of frost before 9am. Otherwise, sunny, with a high near 53. Calm wind becoming northeast around 5 mph in the morning.
Monday Night
Areas of frost after 3am. Otherwise, mostly clear, with a low around 34.
Tuesday
Areas of frost before 9am. Otherwise, mostly sunny, with a high near 55.
Tuesday Night
Mostly clear, with a low around 36.
Wednesday
A slight chance of rain after 4pm. Patchy frost before 7am. Otherwise, mostly sunny, with a high near 54.
Wednesday Night
A chance of rain, mainly after 10pm. Patchy fog. Otherwise, mostly cloudy, with a low around 40.
New Year's Day
A chance of rain. Patchy fog. Otherwise, mostly cloudy, with a high near 54.
Thursday Night
Rain likely. Cloudy, with a low around 44.
Friday
A chance of rain. Mostly cloudy, with a high near 54.
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ABOUT THIS FORECAST

 
Point Forecast:
3 Miles NNE San Ramon CA
 37.8°N 121.93°W (Elev. 640 ft)
7:59 am PST Dec 27, 2025
9am PST Dec 27, 2025-6pm PST Jan 2, 2026
 
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Additional Resources

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