Cucamonga-Guasti Regional Park Weather Forecast

    • 64
    • 91

    Partly Sunny

    • 63
    • 91

    Mostly Sunny

    • 59
    • 87

    Mostly Sunny

    • 58
    • 85

    Mostly Sunny

    • 58
    • 79

    Mostly Sunny

    • 56
    • 77

    Mostly Sunny

    • 56
    • 79

    Mostly Sunny

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

Mostly sunny this morning. Becoming partly cloudy. Warmer. Highs 89 to 98. Areas of Winds west to 10 Mph. Becoming 10 to 15 Mph with Gusts to 25 Mph this afternoon.

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

Partly cloudy. Lows 59 to 65. Areas of Winds west to 10 Mph this evening becoming light.

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Cucamonga-Guasti Regional Park Temperature Statistics

June Temperature

Ontario International Airport (1.2 miles)

  • Lowest 21 June, 2026

    57 °F

  • Average June

    74.5 °F

  • Highest 12 June, 2026

    99.6 °F

Climate (2021–2026)

Ontario International Airport (1.2 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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