Great Falls Weather Forecast

    • 59
    • 82

    Becoming Sunny

    • 62
    • 85

    Mostly Sunny

    • 61
    • 77

    Mostly Cloudy

    • 61
    • 76

    Mostly Cloudy

    • 62
    • 79

    Partly Sunny

    • 63
    • 81

    Partly Sunny

Today 18 Sep Central and Southeast Montgomery

Partly sunny in the Morning, then clearing. Patchy fog in the morning. Highs in the lower 80s. Northwest Winds around 5 Mph.

Tonight 18 Sep Central and Southeast Montgomery

Mostly clear. Lows in the upper 50s. West Winds around 5 Mph.

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Great Falls Temperature Statistics

September Temperature

Washington/Dulles International Airport, DC (9.3 miles)

  • Lowest 8 September, 2025

    48 °F

  • Average September

    69.3 °F

  • Highest 6 September, 2025

    93 °F

Climate (2020–Present)

Washington/Dulles International Airport, DC (9.3 miles)

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  • Average Low 2020–2025

    47.7 °F

  • Average 2020–2025

    58.2 °F

  • Average High 2020–2025

    68.5 °F
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