Potomac River - Rosilie Island Weather Forecast

    • 70
    • 87

    Chance Rain Showers

    • 57
    • 81

    Partly Sunny

    • 60
    • 81

    Mostly Sunny

    • 63
    • 82

    Mostly Sunny

    • 66
    • 85

    Mostly Sunny

    • 66
    • 86

    Chance Rain Showers

Today 13 Sep Arlington/Falls Church/Alexandria

Mostly cloudy with Showers with a slight chance of Thunderstorms in the Morning, then partly sunny in the afternoon. Highs in the mid 80s. West Winds around 5 Mph. Chance of rain 90 percent.

Tonight 13 Sep Arlington/Falls Church/Alexandria

Numerous Showers with a slight chance of Thunderstorms. Lows in the lower 70s. Light and variable Winds. Chance of rain 70 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Potomac River - Rosilie Island Temperature Statistics

September Temperature

Washington/Reagan National Airport, DC (3.7 miles)

  • Lowest 7 September, 2026

    64.7 °F

  • Average September

    80 °F

  • Highest 1 September, 2026

    98.7 °F

Climate (2021–2026)

Washington/Reagan National Airport, DC (3.7 miles)

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  • Average Low 2021–2026

    52.4 °F

  • Average 2021–2026

    60.5 °F

  • Average High 2021–2026

    69.4 °F
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