Ontario International Airport Weather Forecast

    • 72
    • 99

    Slight Chance Thunderstorms

    • 72
    • 99

    Hot

    • 70
    • 96

    Slight Chance Thunderstorms

    • 68
    • 94

    Mostly Sunny

    • 67
    • 91

    Slight Chance Thunderstorms

    • 65
    • 91

    Sunny

Today 23 Aug San Bernardino and Riverside County Valleys-The Inland Empire

Partly cloudy with a slight chance of Showers and Thunderstorms. Highs 97 to 102. Light Winds becoming west 10 Mph in the afternoon. Chance of measurable precipitation 20 percent.

Tonight 23 Aug San Bernardino and Riverside County Valleys-The Inland Empire

Partly cloudy with a slight chance of Showers and Thunderstorms in the Evening, then mostly clear overnight. Lows 69 to 74. Areas of Winds west to 10 Mph in the evening becoming light. Chance of measurable precipitation 20 percent.

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Ontario International Airport Temperature Statistics

August Temperature

Ontario International Airport (1.2 miles)

  • Lowest 1 August, 2025

    61.6 °F

  • Average August

    79.6 °F

  • Highest 7 August, 2025

    103.6 °F

Climate (2020–Present)

Ontario International Airport (1.2 miles)

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  • Average Low 2020–2025

    55.5 °F

  • Average 2020–2025

    66.7 °F

  • Average High 2020–2025

    79.1 °F
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