Sierra Weather Forecast

    • 56
    • 80

    Becoming Sunny

    • 57
    • 84

    Partly Sunny

    • 55
    • 78

    Mostly Cloudy

    • 56
    • 81

    Mostly Sunny

    • 58
    • 84

    Mostly Sunny

    • 61
    • 90

    Mostly Sunny

Today 18 Sep Santa Clara Valley Including San Jose

Mostly cloudy in the morning then becoming sunny. Areas of fog in the morning. Highs near 80. Northwest Winds up to 5 Mph increasing to 5 to 15 Mph in the afternoon.

Tonight 18 Sep Santa Clara Valley Including San Jose

Mostly clear except patchy fog after midnight. Lows in the mid 50s. Northwest Winds 5 to 15 Mph. Becoming west around 5 Mph after midnight.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Sierra Temperature Statistics

September Temperature

San Jose / Reid / Hillv (1.9 miles)

  • Lowest 7 September, 2026

    53.6 °F

  • Average September

    73.6 °F

  • Highest 9 September, 2026

    98.6 °F

Climate (2021–2026)

San Jose / Reid / Hillv (1.9 miles)

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  • Average Low 2021–2026

    52.1 °F

  • Average 2021–2026

    63.7 °F

  • Average High 2021–2026

    72.2 °F
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