Mammoth Weather Forecast

    • 39
    • 55

    Thunderstorms

    • 39
    • 63

    Mostly Sunny

    • 41
    • 67

    Mostly Sunny

    • 44
    • 70

    Partly Sunny

    • 42
    • 67

    Isolated Thunderstorms

    • 40
    • 63

    Isolated Thunderstorms

Today 16 Sep Yellowstone National Park

Widespread fog this morning. Cloudy with numerous rain Showers. Scattered Thunderstorms this afternoon. Highs in the lower 50s. North Winds around 10 Mph with Gusts up to 20 Mph this afternoon. Chance of rain 60 percent.

Tonight 16 Sep Yellowstone National Park

Partly cloudy. Scattered rain Showers with isolated Thunderstorms in the evening. Lows in the mid 30s. Northeast Winds around 10 Mph. Chance of rain 30 percent.

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Mammoth Temperature Statistics

September Temperature

West Yellowstone (28 miles)

  • Lowest 6 September, 2025

    28.4 °F

  • Average September

    54.1 °F

  • Highest 3 September, 2025

    82.4 °F

Climate (2020–Present)

West Yellowstone (28 miles)

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  • Average Low 2020–2025

    33.5 °F

  • Average 2020–2025

    50.8 °F

  • Average High 2020–2025

    66.1 °F
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