Fontana Weather Forecast

    • 68
    • 93

    Mostly Sunny

    • 69
    • 94

    Mostly Sunny

    • 70
    • 97

    Mostly Sunny

    • 71
    • 99

    Hot

    • 71
    • 100

    Hot

    • 70
    • 99

    Mostly Sunny

Today 16 Aug San Bernardino and Riverside County Valleys-The Inland Empire

Partly cloudy this morning. Becoming mostly sunny. Highs 91 to 97. Areas of Winds west to 10 Mph. Becoming 10 to 15 Mph with Gusts to 25 Mph this afternoon.

Tonight 16 Aug San Bernardino and Riverside County Valleys-The Inland Empire

Mostly clear. Lows 62 to 68. Areas of Winds west 10 to 15 Mph in the evening becoming light.

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Fontana Temperature Statistics

August Temperature

Ontario International Airport (8.1 miles)

  • Lowest 14 August, 2026

    66 °F

  • Average August

    83.1 °F

  • Highest 1 August, 2026

    102.7 °F

Climate (2021–2026)

Ontario International Airport (8.1 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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