Marine and Coastal Impacts from Imelda; Unsettled Weather in the West

Swells and high surf from both Imelda and Humberto are expected to bring dangerous marine conditions and rip currents to much of the East Coast over the next several days. A series of Pacific frontal systems will bring waves of showers and thunderstorms to portions of northern California and the Pacific Northwest through midweek. Read More >

Current conditions at

LOS ALTOS (LOAC1)

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

NA

73°F

23°C

Humidity 53%
Wind Speed SSW 2 MPH
Barometer NA
Dewpoint 55°F (13°C)
Visibility NA
Last update 29 Sep 05:10 PM PDT
Extended Forecast for

Portola Valley CA

  • This Afternoon

    This Afternoon: A 40 percent chance of rain.  Partly sunny, with a steady temperature around 73. South southwest wind around 6 mph.

    High: 73 °F

    Chance Rain

  • Tonight

    Tonight: A 40 percent chance of rain.  Mostly cloudy, with a low around 57. South southwest wind around 6 mph becoming calm  after midnight.  New precipitation amounts of less than a tenth of an inch possible.

    Low: 57 °F

    Chance Rain

  • Tuesday

    Tuesday: A 20 percent chance of rain before 11am.  Mostly sunny, with a high near 76. Calm wind becoming south southwest around 6 mph in the afternoon.

    High: 76 °F

    Slight Chance
    Rain then
    Sunny

  • Tuesday Night

    Tuesday Night: A 20 percent chance of rain after 11pm.  Partly cloudy, with a low around 57. Calm wind.

    Low: 57 °F

    Slight Chance
    Rain

  • Wednesday

    Wednesday: A 50 percent chance of rain.  Mostly cloudy, with a high near 76. Calm wind becoming south southeast around 5 mph.  New precipitation amounts of less than a tenth of an inch possible.

    High: 76 °F

    Chance Rain

  • Wednesday Night

    Wednesday Night: A 20 percent chance of rain before 11pm.  Mostly cloudy, with a low around 56. New precipitation amounts of less than a tenth of an inch possible.

    Low: 56 °F

    Slight Chance
    Rain then
    Mostly Cloudy

  • Thursday

    Thursday: Mostly sunny, with a high near 78.

    High: 78 °F

    Mostly Sunny

  • Thursday Night

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

    Low: 53 °F

    Mostly Clear

  • Friday

    Friday: Sunny, with a high near 80.

    High: 80 °F

    Sunny

Detailed Forecast

This Afternoon
A 40 percent chance of rain. Partly sunny, with a steady temperature around 73. South southwest wind around 6 mph.
Tonight
A 40 percent chance of rain. Mostly cloudy, with a low around 57. South southwest wind around 6 mph becoming calm after midnight. New precipitation amounts of less than a tenth of an inch possible.
Tuesday
A 20 percent chance of rain before 11am. Mostly sunny, with a high near 76. Calm wind becoming south southwest around 6 mph in the afternoon.
Tuesday Night
A 20 percent chance of rain after 11pm. Partly cloudy, with a low around 57. Calm wind.
Wednesday
A 50 percent chance of rain. Mostly cloudy, with a high near 76. Calm wind becoming south southeast around 5 mph. New precipitation amounts of less than a tenth of an inch possible.
Wednesday Night
A 20 percent chance of rain before 11pm. Mostly cloudy, with a low around 56. New precipitation amounts of less than a tenth of an inch possible.
Thursday
Mostly sunny, with a high near 78.
Thursday Night
Mostly clear, with a low around 53.
Friday
Sunny, with a high near 80.
Friday Night
Clear, with a low around 53.
Saturday
Sunny, with a high near 82.
Saturday Night
Clear, with a low around 53.
Sunday
Sunny, with a high near 82.
Sunday Night
Mostly clear, with a low around 53.
Monday
Sunny, with a high near 79.
Basemap Options
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ABOUT THIS FORECAST

 
Point Forecast:
Portola Valley CA
 37.39°N 122.23°W (Elev. 397 ft)
1:26 pm PDT Sep 29, 2025
5pm PDT Sep 29, 2025-6pm PDT Oct 6, 2025
 
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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