Granite State Park Weather Forecast

    • 44
    • 64

    Increasing Clouds

    • 43
    • 65

    Partly Sunny

    • 43
    • 65

    Mostly Sunny

    • 36
    • 55

    Slight Chance Thunderstorms

    • 41
    • 58

    Mostly Sunny

    • 43
    • 66

    Mostly Sunny

Today 18 Sep Butte/Blackfoot Region

Mostly sunny. Patchy fog in the morning. Highs in the 70s.

Tonight 18 Sep Butte/Blackfoot Region

Mostly clear. Lows in the 40s.

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Granite State Park Temperature Statistics

September Temperature

Butte, Bert Mooney Airport (43.5 miles)

  • Lowest 12 September, 2025

    37 °F

  • Average September

    58.7 °F

  • Highest 3 September, 2025

    88 °F

Climate (2020–Present)

Butte, Bert Mooney Airport (43.5 miles)

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  • Average Low 2020–2025

    27.7 °F

  • Average 2020–2025

    41.6 °F

  • Average High 2020–2025

    55 °F
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