Big Arm State Park Weather Forecast

    • 52
    • 68

    Rain Showers

    • 49
    • 56

    Rain Showers

    • 48
    • 62

    Rain Likely

    • 52
    • 71

    Mostly Sunny

    • 53
    • 74

    Chance Rain

    • 47
    • 65

    Chance Rain

Today 6 Sep Flathead/Mission Valleys

Mostly cloudy. Areas of rain early in the morning. Chance of rain Showers and a slight chance of Thunderstorms in the afternoon. Chance of precipitation 50 percent. Highs in the upper 60s to mid 70s.

Tonight 6 Sep Flathead/Mission Valleys

Rain Showers likely through the night. Chance of Thunderstorms in the Evening, then slight chance of Thunderstorms after midnight. Patchy fog after midnight. Chance of precipitation 80 percent. Some Thunderstorms may produce small hail and heavy rainfall. Some Thunderstorms may produce heavy rainfall. Lows in the mid 40s to lower 50s.

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  • Temperature Real-Time

Big Arm State Park Temperature Statistics

September Temperature

Kalispell, Glacier Park International Airport (33.6 miles)

  • Lowest 1 September, 2026

    41.6 °F

  • Average September

    58.8 °F

  • Highest 1 September, 2026

    84.7 °F

Climate (2021–2026)

Kalispell, Glacier Park International Airport (33.6 miles)

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  • Average Low 2021–2026

    33.4 °F

  • Average 2021–2026

    45.4 °F

  • Average High 2021–2026

    57 °F
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