Rancho Fontana Weather Forecast

    • 76
    • 105

    Hot

    • 76
    • 104

    Hot

    • 75
    • 102

    Hot

    • 72
    • 101

    Hot

    • 68
    • 97

    Hot

    • 67
    • 93

    Mostly Sunny

Today 26 Aug San Bernardino and Riverside County Valleys-The Inland Empire

Mostly sunny. Highs 103 to 109. Areas of Winds east to 10 Mph becoming west with Gusts to 25 Mph this afternoon.

Tonight 26 Aug San Bernardino and Riverside County Valleys-The Inland Empire

Partly cloudy. Lows 71 to 76. Areas of Winds west 10 to 15 Mph in the evening becoming light.

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  • Temperature Real-Time

Rancho Fontana Temperature Statistics

August Temperature

Ontario International Airport (7.5 miles)

  • Lowest 15 August, 2026

    65.6 °F

  • Average August

    84 °F

  • Highest 23 August, 2026

    105.1 °F

Climate (2021–2026)

Ontario International Airport (7.5 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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