Mammoth Weather Forecast

    • 49
    • 79

    Increasing Clouds

    • 39
    • 71

    Mostly Sunny

    • 48
    • 78

    Sunny

    • 50
    • 85

    Sunny

    • 46
    • 83

    Mostly Sunny

    • 46
    • 81

    Mostly Sunny

Today 13 Sep Northeast Siskiyou and Northwest Modoc Counties

Sunny until early afternoon then becoming partly cloudy. Highs in the mid 70s to lower 80s. Southeast Winds around 5 Mph shifting to the west late this afternoon.

Tonight 13 Sep Northeast Siskiyou and Northwest Modoc Counties

Mostly cloudy. A 10 percent chance of Thunderstorms after midnight. Lows in the mid 40s to lower 50s. West Winds 5 to 10 Mph.

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Mammoth Temperature Statistics

September Temperature

Klamath Falls International Airport (34.2 miles)

  • Lowest 8 September, 2025

    43 °F

  • Average September

    62.6 °F

  • Highest 2 September, 2025

    89.1 °F

Climate (2020–Present)

Klamath Falls International Airport (34.2 miles)

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  • Average Low 2020–2025

    33.8 °F

  • Average 2020–2025

    48.6 °F

  • Average High 2020–2025

    63.1 °F
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