Mount Vernon Weather Forecast

    • 65
    • 89

    Mostly Cloudy

    • 61
    • 84

    Becoming Sunny

    • 63
    • 89

    Mostly Sunny

    • 66
    • 91

    Sunny

    • 69
    • 96

    Sunny

    • 70
    • 98

    Hot

    • 71
    • 98

    Hot

Today 27 Sep San Bernardino and Riverside County Valleys-The Inland Empire

Sunny, hot. Highs 94 to 100.

Tonight 27 Sep San Bernardino and Riverside County Valleys-The Inland Empire

Mostly cloudy this evening. Becoming partly cloudy. Cooler. Lows 59 to 64. Areas of Winds south 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

    73.9 °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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