Grassy Lake Weather Forecast

    • 33
    • 48

    Mostly Sunny

    • 36
    • 53

    Partly Sunny

    • 35
    • 50

    Mostly Sunny

    • 40
    • 52

    Mostly Cloudy

    • 31
    • 47

    Snow Likely

    • 22
    • 34

    Snow Likely

    • 21
    • 31

    Chance Snow

Today 21 Oct Gallatin and Madison County Mountains and Centennial Mountains

Sunny. Highs 40 to 50. Southwest Winds 5 to 15 Mph.

Tonight 21 Oct Gallatin and Madison County Mountains and Centennial Mountains

Partly cloudy. Lows 25 to 30. Southwest Winds 5 to 10 Mph.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Grassy Lake Temperature Statistics

October Temperature

Ennis - Big Sky Airport (11.2 miles)

  • Lowest 6 October, 2025

    23 °F

  • Average October

    45.4 °F

  • Highest 10 October, 2025

    71.6 °F

Climate (2020–Present)

Ennis - Big Sky Airport (11.2 miles)

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  • Average Low 2020–2025

    31.3 °F

  • Average 2020–2025

    43.7 °F

  • Average High 2020–2025

    55.6 °F
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