Big Arm State Park Weather Forecast

    • 46
    • 57

    Rain Showers Likely

    • 47
    • 58

    Chance Rain Showers

    • 47
    • 61

    Mostly Cloudy

    • 49
    • 63

    Mostly Sunny

    • 51
    • 69

    Mostly Sunny

    • 51
    • 69

    Mostly Sunny

    • 51
    • 69

    Mostly Sunny

Today 13 Sep Flathead/Mission Valleys

Rain likely in the Morning, then rain Showers likely and a slight chance of Thunderstorms in the afternoon. Chance of precipitation near 100 percent. Highs in the mid 50s to lower 60s.

Tonight 13 Sep Flathead/Mission Valleys

Mostly cloudy with a chance of rain Showers until early Morning, then rain Showers likely late in the night. Chance of Showers 70 percent. Lows in the upper 30s to mid 40s. Southwest Winds 15 to 25 Mph.

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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 1 September, 2026

    41.6 °F

  • Average September

    58 °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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