Great Falls Weather Forecast

    • 52
    • 82

    Partly Sunny

    • 50
    • 81

    Mostly Sunny

    • 55
    • 86

    Partly Sunny

    • 48
    • 82

    Chance Rain

    • 43
    • 65

    Chance Rain

    • 45
    • 66

    Mostly Cloudy

Today 22 Sep Cascade County below 5000ft

Mostly sunny. Highs around 80. Southwest Winds up to 10 Mph.

Tonight 22 Sep Cascade County below 5000ft

Mostly cloudy. Lows in the lower 50s. Southwest Winds up to 10 Mph.

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Great Falls Temperature Statistics

September Temperature

Great Falls, Great Falls International Airport (3.7 miles)

  • Lowest 17 September, 2026

    39.7 °F

  • Average September

    59.2 °F

  • Highest 1 September, 2026

    86.6 °F

Climate (2021–2026)

Great Falls, Great Falls International Airport (3.7 miles)

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  • Average Low 2021–2026

    34.3 °F

  • Average 2021–2026

    46.9 °F

  • Average High 2021–2026

    59.1 °F
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