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Watching Hurricane Erin; Heavy Rainfall Threat for Upper Midwest; Heatrisk for Mississippi Valley

Hurricane Erin continues to track westward with its outer bands bringing heavy rainfall and gusty winds for Puerto Rico and US Virgin Islands. Life-threatening surf and rip currents are occurring and will spread across the Atlantic coasts this week. Meanwhile, heavy rainfall and possible flooding are in the forecast for upper Midwest through Monday. Heatrisk continues for the Mississippi Valley. Read More >

Current conditions at

LOS ALTOS (LOAC1)

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

NA

73°F

23°C

Humidity 52%
Wind Speed WNW 5 MPH
Barometer NA
Dewpoint 54°F (12°C)
Visibility NA
Last update 17 Aug 12:10 PM PDT
Extended Forecast for

2 Miles NNE Portola Valley CA

  • This Afternoon

    This Afternoon: Sunny, with a high near 76. West wind 9 to 11 mph.

    High: 76 °F

    Sunny

  • Tonight

    Tonight: Partly cloudy, with a low around 54. Southwest wind 3 to 8 mph.

    Low: 54 °F

    Partly Cloudy

  • Monday

    Monday: Sunny, with a high near 79. Calm wind becoming west northwest 5 to 8 mph in the afternoon.

    High: 79 °F

    Sunny

  • Monday Night

    Monday Night: Patchy fog after 3am. Otherwise, mostly clear, with a low around 54. West northwest wind 5 to 9 mph becoming calm in the evening.

    Low: 54 °F

    Clear then
    Patchy Fog

  • Tuesday

    Tuesday: Sunny, with a high near 79. Calm wind becoming west northwest 5 to 8 mph in the afternoon.

    High: 79 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Patchy fog between 1am and 4am. Otherwise, mostly clear, with a low around 55.

    Low: 55 °F

    Mostly Clear
    then Patchy
    Fog

  • Wednesday

    Wednesday: Sunny, with a high near 85.

    High: 85 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 56.

    Low: 56 °F

    Mostly Clear

  • Thursday

    Thursday: Sunny, with a high near 88.

    High: 88 °F

    Sunny

Detailed Forecast

This Afternoon
Sunny, with a high near 76. West wind 9 to 11 mph.
Tonight
Partly cloudy, with a low around 54. Southwest wind 3 to 8 mph.
Monday
Sunny, with a high near 79. Calm wind becoming west northwest 5 to 8 mph in the afternoon.
Monday Night
Patchy fog after 3am. Otherwise, mostly clear, with a low around 54. West northwest wind 5 to 9 mph becoming calm in the evening.
Tuesday
Sunny, with a high near 79. Calm wind becoming west northwest 5 to 8 mph in the afternoon.
Tuesday Night
Patchy fog between 1am and 4am. Otherwise, mostly clear, with a low around 55.
Wednesday
Sunny, with a high near 85.
Wednesday Night
Mostly clear, with a low around 56.
Thursday
Sunny, with a high near 88.
Thursday Night
Mostly clear, with a low around 56.
Friday
Sunny, with a high near 86.
Friday Night
Mostly clear, with a low around 57.
Saturday
Sunny, with a high near 84.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
2 Miles NNE Portola Valley CA
 37.4°N 122.2°W (Elev. 397 ft)
Last Update:
2:33 am PDT Aug 17, 2025
Forecast Valid:
12pm PDT Aug 17, 2025-6pm PDT Aug 23, 2025
 
Forecast Discussion
 
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Additional Resources

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Chance of Precipitation