Fontana Weather Forecast

    • 58
    • 81

    Sunny

    • 54
    • 83

    Sunny

    • 51
    • 82

    Mostly Sunny

    • 53
    • 79

    Mostly Sunny

    • 52
    • 76

    Partly Sunny

    • 50
    • 74

    Mostly Sunny

    • 51
    • 73

    Mostly Sunny

Today 9 Dec San Bernardino and Riverside County Valleys-The Inland Empire

Sunny. Highs 78 to 84. Areas of Winds north 10 to 15 Mph. Gusts to 25 Mph. Becoming 30 Mph this afternoon.

Tonight 9 Dec San Bernardino and Riverside County Valleys-The Inland Empire

Clear, Colder. Lows 37 to 41 in wind Sheltered Areas to 45 to 55 in warmer Locations. Areas of Winds east 10 to 15 Mph with Gusts to 30 Mph.

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Fontana Temperature Statistics

December Temperature

Ontario International Airport (8.1 miles)

  • Lowest 2 December, 2025

    46 °F

  • Average December

    58.4 °F

  • Highest 7 December, 2025

    75.9 °F

Climate (2020–Present)

Ontario International Airport (8.1 miles)

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  • Average Low 2020–2025

    55.5 °F

  • Average 2020–2025

    66.6 °F

  • Average High 2020–2025

    78.9 °F
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