Fontana Weather Forecast

    • 73
    • 101

    Hot

    • 73
    • 102

    Hot

    • 72
    • 102

    Hot

    • 75
    • 102

    Hot

    • 75
    • 105

    Hot

    • 75
    • 106

    Hot

Today 22 Aug San Bernardino and Riverside County Valleys-The Inland Empire

Sunny. Highs 99 to 105. Light Winds becoming west 10 to 15 Mph this afternoon.

Tonight 22 Aug San Bernardino and Riverside County Valleys-The Inland Empire

Mostly clear. Lows 68 to 73. Areas of Winds west 10 to 15 Mph this evening becoming light.

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Fontana Temperature Statistics

August Temperature

Ontario International Airport (8.1 miles)

  • Lowest 15 August, 2026

    65.6 °F

  • Average August

    83.2 °F

  • Highest 19 August, 2026

    103.6 °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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