Grassy Lake Weather Forecast

    • 15
    • 26

    Decreasing Clouds

    • 14
    • 27

    Partly Sunny

    • 10
    • 24

    Partly Sunny

    • 6
    • 19

    Mostly Sunny

    • 13
    • 24

    Partly Sunny

    • 20
    • 30

    Mostly Cloudy

Today 20 Jan Gallatin and Madison County Mountains and Centennial Mountains

Mostly cloudy early in the Morning, then a 20 percent chance of snow late in the morning. Mostly sunny in the afternoon. Highs 21 to 29. West Winds up to 10 Mph with Gusts to around 30 Mph.

Tonight 20 Jan Gallatin and Madison County Mountains and Centennial Mountains

Mostly clear. Lows 6 to 14. West Winds up to 10 Mph with Gusts to around 30 Mph.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Grassy Lake Temperature Statistics

January Temperature

Ennis - Big Sky Airport (11.2 miles)

  • Lowest 17 January, 2026

    14 °F

  • Average January

    33.9 °F

  • Highest 13 January, 2026

    53.6 °F

Climate (2021–Present)

Ennis - Big Sky Airport (11.2 miles)

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  • Average Low 2021–2026

    31.8 °F

  • Average 2021–2026

    44.1 °F

  • Average High 2021–2026

    56 °F
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