Portola Valley Weather Forecast

    • 59
    • 95

    Hot

    • 57
    • 95

    Mostly Sunny

    • 57
    • 84

    Chance Rain Showers

    • 57
    • 82

    Slight Chance Rain Showers

    • 57
    • 83

    Mostly Sunny

    • 59
    • 87

    Mostly Sunny

Today 16 Sep San Francisco Bay Shoreline

Sunny. Highs in the 80s to lower 90s. Light Winds. Becoming northwest 5 to 15 Mph in the afternoon.

Tonight 16 Sep San Francisco Bay Shoreline

Mostly clear. Lows in the lower 60s. Northwest Winds 5 to 10 Mph in the evening. Becoming light.

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Portola Valley Temperature Statistics

September Temperature

Palo Alto Airport (8.1 miles)

  • Lowest 1 September, 2025

    57.2 °F

  • Average September

    69.3 °F

  • Highest 1 September, 2025

    80.6 °F

Climate (2020–Present)

Palo Alto Airport (8.1 miles)

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  • Average Low 2020–2025

    50.9 °F

  • Average 2020–2025

    60.4 °F

  • Average High 2020–2025

    67.2 °F
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