Lake Riverside Weather Forecast

    • 48
    • 78

    Mostly Sunny

    • 49
    • 78

    Mostly Sunny

    • 54
    • 83

    Mostly Sunny

    • 52
    • 82

    Partly Sunny

    • 49
    • 77

    Mostly Sunny

    • 53
    • 81

    Sunny

    • 56
    • 85

    Mostly Sunny

Today 17 Sep Riverside County Mountains

Mostly sunny. Highs 77 to 87.

Tonight 17 Sep Riverside County Mountains

Mostly clear. Lows 45 to 55. Areas of Winds west 10 to 15 Mph.

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Lake Riverside Temperature Statistics

September Temperature

Big Bear City Airport (51.6 miles)

  • Lowest 1 September, 2026

    41.2 °F

  • Average September

    62 °F

  • Highest 10 September, 2026

    81.3 °F

Climate (2021–2026)

Big Bear City Airport (51.6 miles)

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  • Average Low 2021–2026

    33.8 °F

  • Average 2021–2026

    48.8 °F

  • Average High 2021–2026

    60.4 °F
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