Critical Fire Weather in the Southern High Plains; Heavy Snow in the Great Lakes and Northeast U.S.

Gusty winds and low relative humidity will bring elevated to critical fire weather conditions to the southern High Plains through the weekend. A winter storm will track across the Great Lakes and Northeast U.S. into Saturday with areas of wintry mix and heavy snow from northern New York through southern Maine. Read More >

Current conditions at

SJSU - Mount Diablo Summit Museum Rooftop (SJS02)

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

NA

28°F

-2°C

Humidity 99%
Wind Speed N 0 MPH
Barometer NA
Dewpoint 28°F (-2°C)
Visibility NA
Last update 20 Feb 03:25 AM PST
Extended Forecast for

4 Miles SSE Clayton CA

Cold Weather Advisory February 21, 01:00am until February 21, 09:00am
Click here for hazard details and duration
Cold Weather Advisory
  • Overnight

    Overnight: Partly cloudy, with a low around 35. South southeast wind around 9 mph.

    Low: 35 °F

    Partly Cloudy

  • Saturday

    Saturday: Mostly cloudy, then gradually becoming sunny, with a high near 48. South wind 10 to 14 mph, with gusts as high as 26 mph.

    High: 48 °F

    Decreasing
    Clouds

  • Saturday Night

    Saturday Night: Partly cloudy, with a low around 40. South wind around 15 mph, with gusts as high as 28 mph.

    Low: 40 °F

    Partly Cloudy

  • Sunday

    Sunday: Partly sunny, with a high near 56. South southeast wind 8 to 13 mph, with gusts as high as 22 mph.

    High: 56 °F

    Partly Sunny

  • Sunday Night

    Sunday Night: Mostly cloudy, with a low around 44. North northwest wind around 7 mph becoming east northeast after midnight.

    Low: 44 °F

    Mostly Cloudy

  • Monday

    Monday: A 10 percent chance of rain after 4pm.  Partly sunny, with a high near 58.

    High: 58 °F

    Partly Sunny
    then Slight
    Chance Rain

  • Monday Night

    Monday Night: Rain likely, mainly after 4am.  Mostly cloudy, with a low around 53. Chance of precipitation is 60%.

    Low: 53 °F

    Rain Likely

  • Tuesday

    Tuesday: Rain.  Mostly cloudy, with a high near 56.

    High: 56 °F

    Rain

  • Tuesday Night

    Tuesday Night: Rain, mainly before 10pm.  Cloudy, with a low around 53.

    Low: 53 °F

    Rain

Detailed Forecast

Overnight
Partly cloudy, with a low around 35. South southeast wind around 9 mph.
Saturday
Mostly cloudy, then gradually becoming sunny, with a high near 48. South wind 10 to 14 mph, with gusts as high as 26 mph.
Saturday Night
Partly cloudy, with a low around 40. South wind around 15 mph, with gusts as high as 28 mph.
Sunday
Partly sunny, with a high near 56. South southeast wind 8 to 13 mph, with gusts as high as 22 mph.
Sunday Night
Mostly cloudy, with a low around 44. North northwest wind around 7 mph becoming east northeast after midnight.
Monday
A 10 percent chance of rain after 4pm. Partly sunny, with a high near 58.
Monday Night
Rain likely, mainly after 4am. Mostly cloudy, with a low around 53. Chance of precipitation is 60%.
Tuesday
Rain. Mostly cloudy, with a high near 56.
Tuesday Night
Rain, mainly before 10pm. Cloudy, with a low around 53.
Wednesday
A chance of rain. Mostly cloudy, with a high near 56.
Wednesday Night
A chance of rain. Mostly cloudy, with a low around 48.
Thursday
A slight chance of rain. Partly sunny, with a high near 59.
Thursday Night
A slight chance of rain. Mostly cloudy, with a low around 49.
Friday
Mostly sunny, with a high near 61.
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ABOUT THIS FORECAST

 
Point Forecast:
4 Miles SSE Clayton CA
 37.87°N 121.92°W (Elev. 2818 ft)
11:39 pm PST Feb 20, 2026
12am PST Feb 21, 2026-6pm PST Feb 27, 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