Mount Vernon Weather Forecast

    • 51
    • 74

    Partly Sunny

    • 52
    • 76

    Mostly Cloudy

    • 53
    • 69

    Rain Showers

    • 52
    • 64

    Rain Showers

    • 49
    • 63

    Rain Showers

    • 45
    • 61

    Rain Showers

    • 44
    • 62

    Chance Rain Showers

Today 21 Dec San Bernardino and Riverside County Valleys-The Inland Empire

Partly cloudy. Highs 72 to 77. Light Winds.

Tonight 21 Dec San Bernardino and Riverside County Valleys-The Inland Empire

Partly cloudy. Lows 43 to 48 in wind Sheltered Areas to 48 to 56 in warmer Locations. Light Winds.

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Mount Vernon Temperature Statistics

December Temperature

San Bernardino Intl. Airport (4.3 miles)

  • Lowest 4 December, 2025

    40.3 °F

  • Average December

    58.6 °F

  • Highest 10 December, 2025

    87.8 °F

Climate (2020–Present)

San Bernardino Intl. Airport (4.3 miles)

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  • Average Low 2020–2025

    54.1 °F

  • Average 2020–2025

    63.1 °F

  • Average High 2020–2025

    80.3 °F
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