Diamond Bar Weather Forecast

    • 46
    • 64

    Mostly Sunny

    • 47
    • 67

    Increasing Clouds

    • 51
    • 70

    Mostly Cloudy

    • 53
    • 69

    Rain Showers Likely

    • 53
    • 60

    Rain Showers

    • 52
    • 61

    Rain Showers Likely

    • 48
    • 60

    Rain Showers Likely

Today 28 Dec Los Angeles County San Gabriel Valley

Sunny. Highs in the lower to mid 60s.

Tonight 28 Dec Los Angeles County San Gabriel Valley

Mostly clear. Lows in the lower to mid 40s. Northeast Winds around 15 Mph.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Diamond Bar Temperature Statistics

December Temperature

Brackett Field Airport (4.3 miles)

  • Lowest 5 December, 2025

    42.8 °F

  • Average December

    62.8 °F

  • Highest 10 December, 2025

    86 °F

Climate (2020–Present)

Brackett Field Airport (4.3 miles)

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  • Average Low 2020–2025

    55.6 °F

  • Average 2020–2025

    67.6 °F

  • Average High 2020–2025

    75.6 °F
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