Diamond Bar Weather Forecast

    • 72
    • 103

    Hot

    • 70
    • 100

    Hot

    • 69
    • 98

    Hot

    • 68
    • 96

    Sunny

    • 67
    • 95

    Mostly Sunny

    • 64
    • 89

    Mostly Sunny

    • 60
    • 81

    Slight Chance Rain Showers

Today 5 Oct Los Angeles County San Gabriel Valley

Sunny. Highs 99 to 109.

Tonight 5 Oct Los Angeles County San Gabriel Valley

Mostly clear. Lows in the upper 60s and 70s.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Diamond Bar Temperature Statistics

October Temperature

Brackett Field Airport (4.3 miles)

  • Lowest 1 October, 2026

    64.4 °F

  • Average October

    88.1 °F

  • Highest 2 October, 2026

    102.2 °F

Climate (2021–2026)

Brackett Field Airport (4.3 miles)

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  • Average Low 2021–2026

    56.1 °F

  • Average 2021–2026

    68.1 °F

  • Average High 2021–2026

    76 °F
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