Fullerton Weather Forecast

    • 57
    • 70

    Cloudy

    • 55
    • 68

    Rain Showers

    • 55
    • 62

    Rain Showers

    • 54
    • 63

    Rain Likely

    • 51
    • 61

    Chance Rain

    • 49
    • 61

    Chance Rain

    • 49
    • 62

    Slight Chance Rain

Today 30 Dec Los Angeles County San Gabriel Valley

Mostly cloudy. A 20 percent chance of Showers in the morning. Highs around 70. Northeast Winds around 15 Mph.

Tonight 30 Dec Los Angeles County San Gabriel Valley

Cloudy. A 20 percent chance of Showers in the evening. Lows in the mid 50s. Northeast Winds around 15 Mph.

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Fullerton Temperature Statistics

December Temperature

Fullerton, Fullerton Municipal Airport (6.2 miles)

  • Lowest 28 December, 2025

    44.1 °F

  • Average December

    60 °F

  • Highest 10 December, 2025

    84.9 °F

Climate (2020–Present)

Fullerton, Fullerton Municipal Airport (6.2 miles)

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  • Average Low 2020–2025

    56.8 °F

  • Average 2020–2025

    66.1 °F

  • Average High 2020–2025

    76.4 °F
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