Rialto Weather Forecast

    • 54
    • 80

    Becoming Sunny

    • 54
    • 81

    Mostly Sunny

    • 56
    • 83

    Mostly Sunny

    • 53
    • 78

    Mostly Sunny

    • 55
    • 80

    Partly Sunny

    • 53
    • 79

    Partly Sunny

    • 52
    • 74

    Partly Sunny

Today 14 Dec San Bernardino and Riverside County Valleys-The Inland Empire

Partly cloudy. Highs 76 to 81. Light Winds.

Tonight 14 Dec San Bernardino and Riverside County Valleys-The Inland Empire

Mostly clear. Lows 45 to 50 in wind Sheltered Areas to 50 to 58 in warmer Locations. Light Winds.

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Rialto Temperature Statistics

December Temperature

San Bernardino Intl. Airport (6.8 miles)

  • Lowest 4 December, 2025

    40.3 °F

  • Average December

    57.7 °F

  • Highest 10 December, 2025

    87.8 °F

Climate (2020–Present)

San Bernardino Intl. Airport (6.8 miles)

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  • Average Low 2020–2025

    54.1 °F

  • Average 2020–2025

    63 °F

  • Average High 2020–2025

    80.2 °F
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