Walnut Weather Forecast

    • 69
    • 89

    Mostly Sunny

    • 70
    • 89

    Partly Sunny

    • 72
    • 91

    Partly Sunny

    • 67
    • 86

    Partly Sunny

    • 67
    • 82

    Mostly Sunny

    • 70
    • 89

    Mostly Sunny

Today 24 Sep Orange County Inland

Mostly sunny. Highs around 90.

Tonight 24 Sep Orange County Inland

Mostly clear this evening. Becoming partly cloudy. Patchy fog overnight. Lows 64 to 69. Areas of Winds southwest to 10 Mph this evening becoming light.

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Walnut Temperature Statistics

September Temperature

John Wayne-Orange County Airport (4.3 miles)

  • Lowest 2 September, 2026

    65.6 °F

  • Average September

    76.5 °F

  • Highest 9 September, 2026

    102.7 °F

Climate (2021–2026)

John Wayne-Orange County Airport (4.3 miles)

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  • Average Low 2021–2026

    59.1 °F

  • Average 2021–2026

    66.2 °F

  • Average High 2021–2026

    73.8 °F
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