Mammoth Weather Forecast

    • 44
    • 77

    Mostly Sunny

    • 42
    • 71

    Rain Showers

    • 43
    • 71

    Slight Chance Rain

    • 45
    • 75

    Sunny

    • 46
    • 79

    Mostly Sunny

    • 46
    • 83

    Mostly Sunny

Today 15 Sep Northeast Siskiyou and Northwest Modoc Counties

Sunny. Highs in the mid 70s to lower 80s. South Winds around 5 Mph early in the morning becoming Light, then becoming northwest around 5 Mph early in the afternoon increasing to 10 to 15 Mph.

Tonight 15 Sep Northeast Siskiyou and Northwest Modoc Counties

Partly cloudy. A 20 percent chance of Showers after midnight. Lows in the lower to mid 40s. West Winds 10 to 15 Mph decreasing to around 5 Mph well after midnight.

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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

    54.4 °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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