Fullerton Weather Forecast

    • 53
    • 68

    Mostly Cloudy

    • 45
    • 67

    Decreasing Clouds

    • 48
    • 69

    Partly Sunny

    • 47
    • 71

    Partly Sunny

    • 49
    • 73

    Partly Sunny

    • 50
    • 73

    Mostly Cloudy

    • 50
    • 72

    Mostly Sunny

Today 23 Jan Orange County Inland

Partly cloudy. Highs 65 to 68. Light Winds becoming west 10 Mph this afternoon.

Tonight 23 Jan Orange County Inland

Mostly cloudy. Areas of drizzle overnight. Lows 49 to 53. Areas of Winds south 10 Mph this evening becoming light.

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Fullerton Temperature Statistics

January Temperature

Fullerton, Fullerton Municipal Airport (3.1 miles)

  • Lowest 9 January, 2026

    42.1 °F

  • Average January

    62.5 °F

  • Highest 14 January, 2026

    84.9 °F

Climate (2021–Present)

Fullerton, Fullerton Municipal Airport (3.1 miles)

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  • Average Low 2021–2026

    56.9 °F

  • Average 2021–2026

    66.1 °F

  • Average High 2021–2026

    76.4 °F
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