National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Heavy Lake Effect Snow Downwind of Lakes Erie and Ontario; Fire Weather Concerns in the Southern Plains and Southeast

A multi-day heavy lake effect snow event is expected downwind of Lakes Erie and Ontario through New Year's Day. There is increasing confidence in snow squalls causing bursts of snow & gusty winds on New Year's Eve. Elevated fire weather conditions will continue today over parts of the Southern Plains and across much of the Southeast U.S. Read More >

Current conditions at

SJSU - Mount Diablo Summit Museum Rooftop (SJS02)

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

NA

53°F

12°C

Humidity 23%
Wind Speed SSE 7 MPH
Barometer NA
Dewpoint 17°F (-8°C)
Visibility NA
Last update 30 Dec 09:05 AM PST
Extended Forecast for

4 Miles ENE Danville CA

  • Today

    Today: Mostly cloudy, with a high near 54. Northeast wind 6 to 8 mph.

    High: 54 °F

    Mostly Cloudy

  • Tonight

    Tonight: A 10 percent chance of rain after 4am. Cloudy, with a low around 42. Northeast wind around 9 mph.

    Low: 42 °F

    Cloudy then
    Slight Chance
    Rain

  • Wednesday

    Wednesday: Rain, mainly after 10am. High near 52. East northeast wind 5 to 10 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.

    High: 52 °F

    Rain

  • Wednesday Night

    Wednesday Night: Rain. Patchy fog after 1am. Low around 45. East wind 7 to 11 mph. Chance of precipitation is 100%. New precipitation amounts between a quarter and half of an inch possible.

    Low: 45 °F

    Rain and
    Patchy Fog

  • New Year's Day

    New Year's Day: Rain. Areas of fog before 1pm. High near 59. South wind 6 to 8 mph. Chance of precipitation is 90%. New precipitation amounts between a tenth and quarter of an inch possible.

    High: 59 °F

    Rain and
    Areas Fog

  • Thursday Night

    Thursday Night: Rain. Patchy fog. Low around 51. Chance of precipitation is 80%. New precipitation amounts of less than a tenth of an inch possible.

    Low: 51 °F

    Rain and
    Patchy Fog

  • Friday

    Friday: Rain. Patchy fog before 7am. High near 59. Chance of precipitation is 80%.

    High: 59 °F

    Rain and
    Patchy Fog

  • Friday Night

    Friday Night: Rain. Cloudy, with a low around 46.

    Low: 46 °F

    Rain

  • Saturday

    Saturday: Rain likely. Mostly cloudy, with a high near 55.

    High: 55 °F

    Rain Likely

Detailed Forecast

Today
Mostly cloudy, with a high near 54. Northeast wind 6 to 8 mph.
Tonight
A 10 percent chance of rain after 4am. Cloudy, with a low around 42. Northeast wind around 9 mph.
Wednesday
Rain, mainly after 10am. High near 52. East northeast wind 5 to 10 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.
Wednesday Night
Rain. Patchy fog after 1am. Low around 45. East wind 7 to 11 mph. Chance of precipitation is 100%. New precipitation amounts between a quarter and half of an inch possible.
New Year's Day
Rain. Areas of fog before 1pm. High near 59. South wind 6 to 8 mph. Chance of precipitation is 90%. New precipitation amounts between a tenth and quarter of an inch possible.
Thursday Night
Rain. Patchy fog. Low around 51. Chance of precipitation is 80%. New precipitation amounts of less than a tenth of an inch possible.
Friday
Rain. Patchy fog before 7am. High near 59. Chance of precipitation is 80%.
Friday Night
Rain. Cloudy, with a low around 46.
Saturday
Rain likely. Mostly cloudy, with a high near 55.
Saturday Night
Rain likely, mainly before 10pm. Mostly cloudy, with a low around 43.
Sunday
A chance of rain. Patchy fog. Otherwise, partly sunny, with a high near 56.
Sunday Night
A chance of rain. Patchy fog. Otherwise, mostly cloudy, with a low around 43.
Monday
A chance of rain. Patchy fog. Otherwise, mostly cloudy, with a high near 55.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
4 Miles ENE Danville CA
 37.85°N 121.94°W (Elev. 1362 ft)
Last Update:
12:27 am PST Dec 30, 2025
Forecast Valid:
9am PST Dec 30, 2025-6pm PST Jan 5, 2026
 
Forecast Discussion
 
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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

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation