Fontana Weather Forecast

    • 53
    • 66

    Rain Showers

    • 53
    • 62

    Rain Showers

    • 52
    • 63

    Chance Rain Showers

    • 51
    • 63

    Rain Showers Likely

    • 49
    • 62

    Chance Rain Showers

    • 49
    • 62

    Chance Rain Showers

Today 31 Dec San Bernardino and Riverside County Valleys-The Inland Empire

Cloudy. A chance of Showers this Morning, then Showers this afternoon. Highs 63 to 67. Areas of Winds east 10 to 15 Mph with Gusts to 30 Mph.

Tonight 31 Dec San Bernardino and Riverside County Valleys-The Inland Empire

Showers in the Evening, then Showers and a slight chance of Thunderstorms overnight. Locally heavy rainfall possible overnight. Lows 48 to 54. Areas of Winds east 10 Mph.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Fontana Temperature Statistics

December Temperature

Ontario International Airport (8.1 miles)

  • Lowest 28 December, 2025

    43 °F

  • Average December

    60.2 °F

  • Highest 10 December, 2025

    84.9 °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

    79 °F
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