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

Heat the Southwest; Fire Weather in the Central U.S.; Kona Low Impacting Hawaii

A rare March heat wave is ongoing with much above-normal temperatures over the Southwest U.S. through this weekend. Periods of critical fire weather will persist from the central Rockies to the central and southern Plains through the weekend as gusty winds and low relative humidity continue. A Kona low will continue to bring several rounds of moderate to heavy rainfall to Hawaii through Sunday. Read More >

Hazardous Weather Conditions

Current conditions at

SJSU - Mount Diablo Summit Museum Rooftop (SJS02)

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

NA

71°F

22°C

Humidity 8%
Wind Speed N 17 MPH
Barometer NA
Dewpoint 9°F (-13°C)
Visibility NA
Last update 20 Mar 04:05 AM PDT
Extended Forecast for

4 Miles S Clayton CA

Heat Advisory March 20, 07:18am until March 20, 08:00pm
Click here for hazard details and duration
Heat Advisory
  •  
    Heat Advisory March 20, 07:18am until March 20, 08:00pm

    NOW until 8:00pm Fri

    Heat Advisory

  • Today

    High: 84 °F

    Sunny

  • Tonight

    Tonight: Mostly clear, with a low around 67. West wind 8 to 11 mph becoming south southwest after midnight. Winds could gust as high as 21 mph.

    Low: 67 °F

    Mostly Clear

  • Saturday

    Saturday: Mostly sunny, with a high near 77. West southwest wind 9 to 11 mph, with gusts as high as 22 mph.

    High: 77 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 58. West southwest wind 13 to 17 mph, with gusts as high as 30 mph.

    Low: 58 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny, with a high near 76. West northwest wind around 10 mph, with gusts as high as 18 mph.

    High: 76 °F

    Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 50.

    Low: 50 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 70.

    High: 70 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 54.

    Low: 54 °F

    Mostly Clear

Detailed Forecast

Today
Sunny, with a high near 84. North northeast wind 5 to 7 mph becoming northwest in the afternoon.
Tonight
Mostly clear, with a low around 67. West wind 8 to 11 mph becoming south southwest after midnight. Winds could gust as high as 21 mph.
Saturday
Mostly sunny, with a high near 77. West southwest wind 9 to 11 mph, with gusts as high as 22 mph.
Saturday Night
Mostly clear, with a low around 58. West southwest wind 13 to 17 mph, with gusts as high as 30 mph.
Sunday
Sunny, with a high near 76. West northwest wind around 10 mph, with gusts as high as 18 mph.
Sunday Night
Mostly clear, with a low around 50.
Monday
Sunny, with a high near 70.
Monday Night
Mostly clear, with a low around 54.
Tuesday
Sunny, with a high near 72.
Tuesday Night
Mostly clear, with a low around 53.
Wednesday
Sunny, with a high near 69.
Wednesday Night
Mostly clear, with a low around 52.
Thursday
Sunny, with a high near 69.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
4 Miles S Clayton CA
 37.87°N 121.92°W (Elev. 2818 ft)
Last Update:
2:22 am PDT Mar 20, 2026
Forecast Valid:
7am PDT Mar 20, 2026-6pm PDT Mar 26, 2026
 
Forecast Discussion
 
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Additional Resources

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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