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

72°F

22°C

Humidity 21%
Wind Speed N 8 MPH
Barometer NA
Dewpoint 30°F (-1°C)
Visibility NA
Last update 20 Mar 11:30 AM PDT
Extended Forecast for

4 Miles SSE Clayton CA

Heat Advisory March 20, 12:20pm until March 20, 08:00pm
Click here for hazard details and duration
Heat Advisory
  •  
    Heat Advisory March 20, 12:20pm until March 20, 08:00pm

    NOW until 8:00pm Fri

    Heat Advisory

  • This Afternoon

    High: 81 °F

    Sunny

  • Tonight

    Tonight: Mostly clear, with a low around 63. Southwest wind 9 to 11 mph, with gusts as high as 21 mph.

    Low: 63 °F

    Mostly Clear

  • Saturday

    Saturday: Mostly sunny, with a high near 74. Southwest wind 9 to 15 mph becoming west northwest in the afternoon. Winds could gust as high as 26 mph.

    High: 74 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 54. West southwest wind 13 to 17 mph, with gusts as high as 31 mph.

    Low: 54 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny, with a high near 69. West northwest wind around 9 mph.

    High: 69 °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 68.

    High: 68 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 53.

    Low: 53 °F

    Mostly Clear

Detailed Forecast

This Afternoon
Sunny, with a steady temperature around 81. North wind around 6 mph.
Tonight
Mostly clear, with a low around 63. Southwest wind 9 to 11 mph, with gusts as high as 21 mph.
Saturday
Mostly sunny, with a high near 74. Southwest wind 9 to 15 mph becoming west northwest in the afternoon. Winds could gust as high as 26 mph.
Saturday Night
Mostly clear, with a low around 54. West southwest wind 13 to 17 mph, with gusts as high as 31 mph.
Sunday
Sunny, with a high near 69. West northwest wind around 9 mph.
Sunday Night
Mostly clear, with a low around 50.
Monday
Sunny, with a high near 68.
Monday Night
Mostly clear, with a low around 53.
Tuesday
Sunny, with a high near 71.
Tuesday Night
Mostly clear, with a low around 52.
Wednesday
Sunny, with a high near 68.
Wednesday Night
Mostly clear, with a low around 51.
Thursday
Mostly sunny, with a high near 68.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
4 Miles SSE Clayton CA
 37.87°N 121.92°W (Elev. 2818 ft)
Last Update:
11:52 am PDT Mar 20, 2026
Forecast Valid:
12pm PDT Mar 20, 2026-6pm PDT Mar 26, 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