Fullerton Weather Forecast

    • 66
    • 92

    Slight Chance Thunderstorms

    • 66
    • 94

    Mostly Sunny

    • 66
    • 90

    Mostly Sunny

    • 63
    • 86

    Mostly Sunny

    • 63
    • 86

    Sunny

    • 64
    • 86

    Mostly Sunny

    • 65
    • 85

    Mostly Sunny

Today 23 Aug Los Angeles County San Gabriel Valley

Partly cloudy. A slight chance of Showers in the Morning, then a chance of Showers with a slight chance of Thunderstorms in the afternoon. Highs in the lower to mid 90s. Chance of precipitation 30 percent.

Tonight 23 Aug Los Angeles County San Gabriel Valley

Partly cloudy in the evening then mostly clear. Lows in the mid 60s to around 70.

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Fullerton Temperature Statistics

August Temperature

Fullerton, Fullerton Municipal Airport (6.2 miles)

  • Lowest 3 August, 2025

    63.6 °F

  • Average August

    75.5 °F

  • Highest 7 August, 2025

    95.6 °F

Climate (2020–Present)

Fullerton, Fullerton Municipal Airport (6.2 miles)

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  • Average Low 2020–2025

    56.7 °F

  • Average 2020–2025

    66.1 °F

  • Average High 2020–2025

    76.7 °F
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