Flathead Lake State Park - Yellow Bay Unit Weather Forecast

    • 43
    • 56

    Increasing Clouds

    • 47
    • 59

    Gradual Clearing

    • 49
    • 63

    Mostly Sunny

    • 54
    • 64

    Chance Rain

    • 51
    • 63

    Slight Chance Rain

    • 52
    • 64

    Partly Sunny

    • 50
    • 63

    Partly Sunny

Today 26 Sep Flathead/Mission Valleys

Partly cloudy. Highs in the 60s.

Tonight 26 Sep Flathead/Mission Valleys

Mostly clear until early morning then becoming mostly cloudy. Lows in the 30s.

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  • Temperature Real-Time

Flathead Lake State Park - Yellow Bay Unit Temperature Statistics

September Temperature

Kalispell, Glacier Park International Airport (31.1 miles)

  • Lowest 24 September, 2026

    37.9 °F

  • Average September

    56.8 °F

  • Highest 1 September, 2026

    84.7 °F

Climate (2021–2026)

Kalispell, Glacier Park International Airport (31.1 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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