Big Sky Weather Forecast

    • 46
    • 68

    Rain Showers Likely

    • 44
    • 60

    Rain

    • 42
    • 49

    Rain Showers

    • 41
    • 60

    Chance Rain Showers

    • 44
    • 63

    Partly Sunny

    • 42
    • 63

    Partly Sunny

    • 43
    • 63

    Partly Sunny

Today 17 Sep Gallatin and Madison County Mountains and Centennial Mountains

Mostly sunny. Highs 58 to 68.

Tonight 17 Sep Gallatin and Madison County Mountains and Centennial Mountains

Mostly cloudy then becoming partly cloudy late in the evening then becoming mostly cloudy. Chance of Thunderstorms early in the evening. Slight chance of Thunderstorms in the late evening and overnight. Chance of rain Showers after midnight. Lows 42 to 48. South Winds up to 15 Mph. Chance of precipitation 50 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Big Sky Temperature Statistics

September Temperature

Ennis - Big Sky Airport (13.7 miles)

  • Lowest 15 September, 2026

    30.2 °F

  • Average September

    58.8 °F

  • Highest 6 September, 2026

    82.4 °F

Climate (2021–2026)

Ennis - Big Sky Airport (13.7 miles)

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  • Average Low 2021–2026

    32 °F

  • Average 2021–2026

    44.4 °F

  • Average High 2021–2026

    56.4 °F
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