Severe Thunderstorms and Flooding from the Southern Plains to the Great Lakes; Record Heat in the East

Widely scattered severe thunderstorms may produce damaging winds, hail, and flash flooding from the southern Plains into the lower Great Lakes. Elevated to locally critical fire weather conditions will persist across portions of the Southwest and Southern High Plains due to gusty winds and dry conditions. An early-season heatwave will challenge temperature records across the eastern U.S.. Read More >

Current conditions at

LOS ALTOS (LOAC1)

Lat: 37.35472°NLon: 122.14167°WElev: 539.0ft.

NA

59°F

15°C

Humidity 35%
Wind Speed WSW 2 MPH
Barometer NA
Dewpoint 31°F (-1°C)
Visibility NA
Last update 20 May 02:10 AM PDT
Extended Forecast for

3 Miles NW Portola Valley CA

  • Overnight

    Overnight: Clear, with a low around 53. Calm wind.

    Low: 53 °F

    Clear

  • Wednesday

    Wednesday: Sunny, with a high near 83. Calm wind becoming southwest around 5 mph in the afternoon.

    High: 83 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Clear, with a low around 50. Calm wind.

    Low: 50 °F

    Clear

  • Thursday

    Thursday: Sunny, with a high near 83. Calm wind becoming west around 5 mph in the afternoon.

    High: 83 °F

    Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 50. West wind around 5 mph becoming calm  in the evening.

    Low: 50 °F

    Mostly Clear

  • Friday

    Friday: Sunny, with a high near 79.

    High: 79 °F

    Sunny

  • Friday Night

    Friday Night: Partly cloudy, with a low around 51.

    Low: 51 °F

    Partly Cloudy

  • Saturday

    Saturday: Mostly sunny, with a high near 74.

    High: 74 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: Partly cloudy, with a low around 50.

    Low: 50 °F

    Partly Cloudy

Detailed Forecast

Overnight
Clear, with a low around 53. Calm wind.
Wednesday
Sunny, with a high near 83. Calm wind becoming southwest around 5 mph in the afternoon.
Wednesday Night
Clear, with a low around 50. Calm wind.
Thursday
Sunny, with a high near 83. Calm wind becoming west around 5 mph in the afternoon.
Thursday Night
Mostly clear, with a low around 50. West wind around 5 mph becoming calm in the evening.
Friday
Sunny, with a high near 79.
Friday Night
Partly cloudy, with a low around 51.
Saturday
Mostly sunny, with a high near 74.
Saturday Night
Partly cloudy, with a low around 50.
Sunday
Mostly sunny, with a high near 71.
Sunday Night
Mostly clear, with a low around 48.
Memorial Day
Mostly sunny, with a high near 71.
Monday Night
Mostly clear, with a low around 48.
Tuesday
Mostly sunny, with a high near 68.
Basemap Options
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ABOUT THIS FORECAST

 
Point Forecast:
3 Miles NW Portola Valley CA
 37.41°N 122.26°W (Elev. 535 ft)
1:26 am PDT May 20, 2026
2am PDT May 20, 2026-6pm PDT May 26, 2026
 
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Additional Resources

Radar & Satellite Image

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Hourly Weather Forecast

National Digital Forecast Database