Mount Vernon Weather Forecast

    • 69
    • 82

    Rain Showers

    • 71
    • 92

    Mostly Sunny

    • 73
    • 95

    Mostly Sunny

    • 75
    • 99

    Hot

    • 74
    • 99

    Hot

    • 69
    • 97

    Hot

Today 6 Sep San Bernardino and Riverside County Valleys-The Inland Empire

Cloudy with Showers likely this Morning, then mostly cloudy with a chance of Showers and a slight chance of Thunderstorms this afternoon. Highs 80 to 85. Areas of Winds north to 10 Mph this morning becoming light. Chance of measurable precipitation 70 percent.

Tonight 6 Sep San Bernardino and Riverside County Valleys-The Inland Empire

Partly cloudy. A slight chance of Showers in the evening. Lows 65 to 69. Light Winds. Chance of measurable precipitation 20 percent.

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Mount Vernon Temperature Statistics

September Temperature

San Bernardino Intl. Airport (4.3 miles)

  • Lowest 2 September, 2026

    59 °F

  • Average September

    71.2 °F

  • Highest 1 September, 2026

    91.4 °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

    80.4 °F
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