Rancho Cucamonga Weather Forecast

    • 63
    • 88

    Mostly Sunny

    • 64
    • 90

    Mostly Sunny

    • 65
    • 91

    Mostly Sunny

    • 67
    • 93

    Mostly Sunny

    • 67
    • 95

    Mostly Sunny

    • 68
    • 96

    Mostly Sunny

    • 68
    • 96

    Mostly Sunny

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

Partly cloudy with patchy fog this morning. Becoming sunny. Highs 84 to 90. Light Winds becoming southwest 10 to 15 Mph with Gusts to 25 Mph this afternoon.

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

Mostly clear this evening. Becoming partly cloudy. Lows 58 to 63. Areas of Winds west 10 to 15 Mph with Gusts to 25 Mph this evening becoming light.

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Rancho Cucamonga Temperature Statistics

August Temperature

Ontario International Airport (3.7 miles)

  • Lowest 5 August, 2026

    66.7 °F

  • Average August

    83.8 °F

  • Highest 1 August, 2026

    102.7 °F

Climate (2021–2026)

Ontario International Airport (3.7 miles)

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  • Average Low 2021–2026

    55.8 °F

  • Average 2021–2026

    67.1 °F

  • Average High 2021–2026

    79.3 °F
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