Ontario Weather Forecast

    • 70
    • 99

    Hot

    • 69
    • 97

    Hot

    • 68
    • 94

    Partly Sunny

    • 66
    • 91

    Partly Sunny

    • 64
    • 89

    Partly Sunny

    • 64
    • 86

    Partly Sunny

    • 64
    • 86

    Mostly Sunny

Today 8 Aug San Bernardino and Riverside County Valleys-The Inland Empire

Mostly sunny. Highs 97 to 104. Light Winds becoming west 10 to 15 Mph with Gusts to 25 Mph this afternoon.

Tonight 8 Aug San Bernardino and Riverside County Valleys-The Inland Empire

Clear. Lows 65 to 71. Areas of Winds west to 10 Mph this evening becoming light.

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Ontario Temperature Statistics

August Temperature

Ontario International Airport (3.7 miles)

  • Lowest 5 August, 2026

    66.7 °F

  • Average August

    83 °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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