Big Sky Weather Forecast

    • 45
    • 67

    Decreasing Clouds

    • 47
    • 67

    Partly Sunny

    • 44
    • 65

    Chance Thunderstorms

    • 44
    • 63

    Chance Rain Showers

    • 42
    • 61

    Rain Showers Likely

    • 40
    • 57

    Rain Showers Likely

    • 41
    • 56

    Chance Rain Showers

Today 7 Sep Gallatin and Madison County Mountains and Centennial Mountains

Mostly cloudy. Slight chance of rain Showers in the Morning, then chance of Thunderstorms in the afternoon. Areas of smoke in the morning. Haze through the day. Highs 65 to 75. Southwest Winds 5 to 15 Mph. Chance of precipitation 50 percent.

Tonight 7 Sep Gallatin and Madison County Mountains and Centennial Mountains

Colder. Mostly cloudy with a 50 percent chance of Thunderstorms in the Evening, then partly cloudy after midnight. Lows 40 to 50. Southwest Winds 5 to 15 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

    62.7 °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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