Island Park Reservoir Weather Forecast

    • 39
    • 60

    Thunderstorms

    • 39
    • 64

    Chance Rain Showers

    • 40
    • 69

    Sunny

    • 41
    • 71

    Mostly Sunny

    • 43
    • 72

    Partly Sunny

    • 43
    • 71

    Partly Sunny

    • 39
    • 68

    Chance Rain Showers

Today 15 Sep Centennial Mountains/Island Park

A chance of rain Showers and a slight chance of Thunderstorms in the morning. Then rain Showers likely and a chance of Thunderstorms in the afternoon. Highs 58 to 66.

Tonight 15 Sep Centennial Mountains/Island Park

Partly cloudy. Scattered rain Showers and isolated Thunderstorms in the evening. Then isolated rain Showers after midnight. Lows 36 to 46.

Graph Plots Open in Graphs

  • Temperature Forecast NOAA

  • Temperature Real-Time

Island Park Reservoir Temperature Statistics

September Temperature

West Yellowstone (27.3 miles)

  • Lowest 6 September, 2025

    28.4 °F

  • Average September

    54.4 °F

  • Highest 3 September, 2025

    82.4 °F

Climate (2020–Present)

West Yellowstone (27.3 miles)

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

  • Average Low 2020–2025

    33.5 °F

  • Average 2020–2025

    50.8 °F

  • Average High 2020–2025

    66.1 °F
Get WillyWeather+ to remove ads