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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

59°F

15°C

Humidity 75%
Wind Speed WNW 0 MPH
Barometer NA
Dewpoint 51°F (11°C)
Visibility NA
Last update 18 Aug 12:10 AM PDT
Extended Forecast for

Portola Valley CA

  • Overnight

    Overnight: Mostly clear, with a low around 52. West wind 3 to 6 mph.

    Low: 52 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 74. Calm wind becoming west northwest 5 to 8 mph in the afternoon.

    High: 74 °F

    Sunny

  • Monday Night

    Monday Night: Clear, with a low around 52. West wind 3 to 7 mph.

    Low: 52 °F

    Clear

  • Tuesday

    Tuesday: Sunny, with a high near 73. West northwest wind 3 to 7 mph.

    High: 73 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 54. West wind 5 to 9 mph.

    Low: 54 °F

    Mostly Clear

  • Wednesday

    Wednesday: Sunny, with a high near 79.

    High: 79 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Clear, with a low around 56.

    Low: 56 °F

    Clear

  • Thursday

    Thursday: Sunny, with a high near 84.

    High: 84 °F

    Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 57.

    Low: 57 °F

    Mostly Clear

Detailed Forecast

Overnight
Mostly clear, with a low around 52. West wind 3 to 6 mph.
Monday
Sunny, with a high near 74. Calm wind becoming west northwest 5 to 8 mph in the afternoon.
Monday Night
Clear, with a low around 52. West wind 3 to 7 mph.
Tuesday
Sunny, with a high near 73. West northwest wind 3 to 7 mph.
Tuesday Night
Mostly clear, with a low around 54. West wind 5 to 9 mph.
Wednesday
Sunny, with a high near 79.
Wednesday Night
Clear, with a low around 56.
Thursday
Sunny, with a high near 84.
Thursday Night
Mostly clear, with a low around 57.
Friday
Sunny, with a high near 80.
Friday Night
Mostly clear, with a low around 57.
Saturday
Sunny, with a high near 78.
Saturday Night
Mostly clear, with a low around 56.
Sunday
Sunny, with a high near 78.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Portola Valley CA
 37.35°N 122.21°W (Elev. 1440 ft)
Last Update:
12:26 am PDT Aug 18, 2025
Forecast Valid:
12am PDT Aug 18, 2025-6pm PDT Aug 24, 2025
 
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