Big Sky Weather Forecast

    • 39
    • 52

    Rain Showers Likely

    • 40
    • 61

    Mostly Sunny

    • 43
    • 64

    Sunny

    • 46
    • 66

    Mostly Sunny

    • 45
    • 66

    Partly Sunny

    • 40
    • 61

    Partly Sunny

Today 16 Sep Gallatin and Madison County Mountains and Centennial Mountains

Mostly cloudy. Chance of rain in the Morning, then chance of rain Showers and slight chance of Thunderstorms in the afternoon. Highs 50 to 60. North Winds 5 to 15 Mph. Chance of precipitation 50 percent.

Tonight 16 Sep Gallatin and Madison County Mountains and Centennial Mountains

Partly cloudy. Lows 35 to 40. Northeast Winds up to 10 Mph.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Big Sky Temperature Statistics

September Temperature

Ennis - Big Sky Airport (13.7 miles)

  • Lowest 5 September, 2025

    39.2 °F

  • Average September

    61.7 °F

  • Highest 2 September, 2025

    87.8 °F

Climate (2020–Present)

Ennis - Big Sky Airport (13.7 miles)

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  • Average Low 2020–2025

    31.3 °F

  • Average 2020–2025

    43.7 °F

  • Average High 2020–2025

    55.7 °F
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