Brentwood Weather Forecast

    • 69
    • 94

    Mostly Sunny

    • 70
    • 96

    Mostly Sunny

    • 71
    • 97

    Hot

    • 71
    • 98

    Hot

    • 70
    • 97

    Hot

    • 70
    • 97

    Hot

Today 17 Aug San Bernardino and Riverside County Valleys-The Inland Empire

Mostly sunny. Highs 93 to 100. Light Winds becoming west 10 to 15 Mph with Gusts to 25 Mph this afternoon.

Tonight 17 Aug San Bernardino and Riverside County Valleys-The Inland Empire

Mostly clear. Lows 64 to 69. Areas of Winds west to 10 Mph in the evening becoming light.

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Brentwood Temperature Statistics

August Temperature

Ontario International Airport (8.1 miles)

  • Lowest 15 August, 2026

    64.9 °F

  • Average August

    82.8 °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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