Big Arm State Park Weather Forecast

    • 52
    • 61

    Slight Chance Rain

    • 54
    • 71

    Becoming Sunny

    • 53
    • 73

    Mostly Sunny

    • 54
    • 75

    Mostly Sunny

    • 55
    • 75

    Partly Sunny

    • 54
    • 74

    Partly Sunny

    • 49
    • 66

    Slight Chance Rain

Today 15 Sep Flathead/Mission Valleys

Rain Showers likely in the Morning, then chance of rain Showers in the afternoon. Slight chance of Thunderstorms early in the afternoon. Chance of precipitation 60 percent. Highs in the 60s.

Tonight 15 Sep Flathead/Mission Valleys

Mostly cloudy. Patchy fog in the late evening and overnight. A 20 percent chance of rain late in the evening. Lows in the 40s.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Big Arm State Park Temperature Statistics

September Temperature

Kalispell, Glacier Park International Airport (33.6 miles)

  • Lowest 9 September, 2025

    44.1 °F

  • Average September

    67.6 °F

  • Highest 2 September, 2025

    93.2 °F

Climate (2020–Present)

Kalispell, Glacier Park International Airport (33.6 miles)

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  • Average Low 2020–2025

    33.1 °F

  • Average 2020–2025

    45.2 °F

  • Average High 2020–2025

    56.8 °F
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