Alta Loma Weather Forecast

    • 56
    • 78

    Increasing Clouds

    • 56
    • 79

    Mostly Sunny

    • 55
    • 76

    Mostly Sunny

    • 54
    • 77

    Mostly Sunny

    • 56
    • 81

    Mostly Sunny

    • 59
    • 86

    Mostly Sunny

Today 14 May San Bernardino and Riverside County Valleys-The Inland Empire

Partly cloudy with patchy fog this morning. Becoming sunny. Highs 77 to 82. Areas of Winds southwest to 10 Mph becoming west with Gusts to 25 Mph this afternoon.

Tonight 14 May San Bernardino and Riverside County Valleys-The Inland Empire

Clear in the evening. Becoming partly cloudy overnight with patchy fog. Lows 51 to 56. Areas of Winds west 10 to 15 Mph with Gusts to 25 Mph in the evening becoming light.

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Alta Loma Temperature Statistics

May Temperature

Ontario International Airport (4.3 miles)

  • Lowest 6 May, 2026

    49.6 °F

  • Average May

    68.3 °F

  • Highest 11 May, 2026

    95 °F

Climate (2021–Present)

Ontario International Airport (4.3 miles)

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  • Average Low 2021–2026

    55.8 °F

  • Average 2021–2026

    67 °F

  • Average High 2021–2026

    79.4 °F
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