Foster City Weather Forecast

    • 59
    • 84

    Mostly Sunny

    • 60
    • 82

    Partly Sunny

    • 55
    • 75

    Partly Sunny

    • 55
    • 74

    Partly Sunny

    • 55
    • 69

    Mostly Sunny

    • 57
    • 79

    Sunny

Today 23 Sep San Francisco Bay Shoreline

Sunny. Highs in the upper 70s to mid 80s. Light Winds. Becoming northwest 10 to 20 Mph in the afternoon.

Tonight 23 Sep San Francisco Bay Shoreline

Mostly clear in the evening then becoming partly cloudy. Lows in the upper 50s. West Winds 10 to 15 Mph. Becoming southwest up to 5 Mph after midnight.

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Foster City Temperature Statistics

September Temperature

San Carlos Airport (3.1 miles)

  • Lowest 7 September, 2026

    53.6 °F

  • Average September

    64.6 °F

  • Highest 9 September, 2026

    98.6 °F

Climate (2021–2026)

San Carlos Airport (3.1 miles)

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  • Average Low 2021–2026

    51.8 °F

  • Average 2021–2026

    57 °F

  • Average High 2021–2026

    68.3 °F
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