Mount Vernon Weather Forecast

    • 69
    • 97

    Hot

    • 70
    • 94

    Mostly Sunny

    • 70
    • 94

    Mostly Cloudy

    • 63
    • 86

    Mostly Sunny

    • 61
    • 82

    Sunny

    • 64
    • 88

    Mostly Sunny

    • 66
    • 91

    Sunny

Today 24 Sep San Bernardino and Riverside County Valleys-The Inland Empire

Mostly sunny. Highs 89 to 95.

Tonight 24 Sep San Bernardino and Riverside County Valleys-The Inland Empire

Mostly clear. Lows 63 to 68. Areas of Winds west to 10 Mph this evening becoming light.

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Mount Vernon Temperature Statistics

September Temperature

San Bernardino Intl. Airport (4.3 miles)

  • Lowest 19 September, 2026

    57.2 °F

  • Average September

    73.8 °F

  • Highest 9 September, 2026

    105.8 °F

Climate (2021–2026)

San Bernardino Intl. Airport (4.3 miles)

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  • Average Low 2021–2026

    54.2 °F

  • Average 2021–2026

    63.2 °F

  • Average High 2021–2026

    80.3 °F
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