Diamond Bar Weather Forecast

    • 55
    • 81

    Mostly Sunny

    • 57
    • 82

    Sunny

    • 54
    • 80

    Mostly Cloudy

    • 52
    • 69

    Mostly Sunny

    • 54
    • 73

    Mostly Sunny

    • 55
    • 78

    Mostly Sunny

Today 19 Oct Los Angeles County San Gabriel Valley

Partly cloudy. Highs in the upper 70s to mid 80s.

Tonight 19 Oct Los Angeles County San Gabriel Valley

Partly cloudy in the evening then mostly clear. Lows in the mid 50s.

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Diamond Bar Temperature Statistics

October Temperature

Brackett Field Airport (4.3 miles)

  • Lowest 16 October, 2025

    50 °F

  • Average October

    68.5 °F

  • Highest 10 October, 2025

    87.8 °F

Climate (2020–Present)

Brackett Field Airport (4.3 miles)

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  • Average Low 2020–2025

    55.4 °F

  • Average 2020–2025

    67.6 °F

  • Average High 2020–2025

    75.5 °F
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