Great Falls Weather Forecast

    • 54
    • 61

    Rain Showers

    • 53
    • 62

    Rain Showers Likely

    • 50
    • 63

    Mostly Cloudy

    • 52
    • 66

    Partly Sunny

    • 54
    • 67

    Partly Sunny

    • 54
    • 70

    Partly Sunny

Today 22 Sep Central and Southeast Montgomery

Rain. Patchy fog. Highs in the lower 60s. Northeast Winds 10 to 15 Mph with Gusts up to 25 Mph. Chance of rain 90 percent.

Tonight 22 Sep Central and Southeast Montgomery

Rain, mainly in the evening. Patchy fog. Lows in the mid 50s. Northeast Winds 10 to 15 Mph with Gusts up to 25 Mph. Chance of rain 90 percent.

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Great Falls Temperature Statistics

September Temperature

Washington/Dulles International Airport, DC (9.3 miles)

  • Lowest 15 September, 2026

    52.6 °F

  • Average September

    75.7 °F

  • Highest 1 September, 2026

    94.6 °F

Climate (2021–2026)

Washington/Dulles International Airport, DC (9.3 miles)

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  • Average Low 2021–2026

    47.6 °F

  • Average 2021–2026

    58.3 °F

  • Average High 2021–2026

    68.6 °F
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