South Arm Weather Forecast

    • 35
    • 59

    Decreasing Clouds

    • 39
    • 65

    Mostly Sunny

    • 42
    • 66

    Partly Sunny

    • 42
    • 64

    Mostly Sunny

    • 39
    • 62

    Slight Chance Thunderstorms

    • 41
    • 62

    Mostly Sunny

Today 17 Sep Yellowstone National Park

Partly cloudy this Morning, then clearing. Highs in the lower 60s. Northeast Winds around 10 Mph.

Tonight 17 Sep Yellowstone National Park

Mostly clear. Lows in the lower 30s. Northeast Winds around 10 Mph in the evening.

Graph Plots Open in Graphs

  • Temperature Forecast NOAA

  • Temperature Real-Time

South Arm Temperature Statistics

September Temperature

Yellowstone Lake (14.9 miles)

  • Lowest 6 September, 2025

    30.9 °F

  • Average September

    50.8 °F

  • Highest 3 September, 2025

    75.9 °F

Climate (2020–Present)

Yellowstone Lake (14.9 miles)

Take a look at our website widgetsAvailable free! Find Out More

  • Average Low 2020–2025

    22.3 °F

  • Average 2020–2025

    35.2 °F

  • Average High 2020–2025

    48 °F
Get WillyWeather+ to remove ads