Mammoth Weather Forecast

    • 44
    • 78

    Increasing Clouds

    • 45
    • 78

    Partly Sunny

    • 46
    • 79

    Partly Sunny

    • 37
    • 65

    Slight Chance Rain

    • 39
    • 66

    Partly Sunny

    • 37
    • 64

    Mostly Sunny

Today 22 Sep Northeast Siskiyou and Northwest Modoc Counties

Partly cloudy until early afternoon then becoming sunny. Highs in the mid 70s to lower 80s. West Winds 10 to 15 Mph.

Tonight 22 Sep Northeast Siskiyou and Northwest Modoc Counties

Mostly clear. Lows in the lower to mid 40s. West Winds 5 to 10 Mph.

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Mammoth Temperature Statistics

September Temperature

Klamath Falls International Airport (34.2 miles)

  • Lowest 7 September, 2026

    31.6 °F

  • Average September

    54.8 °F

  • Highest 10 September, 2026

    86.6 °F

Climate (2021–2026)

Klamath Falls International Airport (34.2 miles)

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  • Average Low 2021–2026

    33.9 °F

  • Average 2021–2026

    48.6 °F

  • Average High 2021–2026

    63.3 °F
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