Saint Marys Lake Weather Forecast

    • 51
    • 69

    Mostly Sunny

    • 53
    • 72

    Mostly Sunny

    • 53
    • 72

    Partly Sunny

    • 50
    • 69

    Partly Sunny

    • 53
    • 71

    Partly Sunny

    • 49
    • 65

    Slight Chance Rain

Today 20 Sep Potomac/Seeley Lake Region

Mostly cloudy. Highs in the mid 50s to lower 60s.

Tonight 20 Sep Potomac/Seeley Lake Region

Mostly clear. Patchy fog late in the night. Lows in the 40s.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Saint Marys Lake Temperature Statistics

September Temperature

Missoula, Missoula International Airport (24.9 miles)

  • Lowest 9 September, 2026

    38.6 °F

  • Average September

    58.5 °F

  • Highest 1 September, 2026

    88.6 °F

Climate (2021–2026)

Missoula, Missoula International Airport (24.9 miles)

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  • Average Low 2021–2026

    36 °F

  • Average 2021–2026

    47.6 °F

  • Average High 2021–2026

    59.7 °F
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