Lake Mercer Weather Forecast

    • 61
    • 81

    Mostly Sunny

    • 64
    • 87

    Increasing Clouds

    • 63
    • 83

    Mostly Cloudy

    • 61
    • 76

    Chance Rain Showers

    • 61
    • 77

    Chance Rain Showers

    • 63
    • 82

    Slight Chance Thunderstorms

    • 64
    • 86

    Partly Sunny

Today 13 Sep Fairfax

Sunny. Highs in the lower 80s. South Winds 5 to 10 Mph.

Tonight 13 Sep Fairfax

Mostly clear this Evening, then becoming partly cloudy. Lows in the lower 60s. South Winds 5 to 10 Mph.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Lake Mercer Temperature Statistics

September Temperature

Fort Belvoir (4.3 miles)

  • Lowest 9 September, 2025

    49.8 °F

  • Average September

    67.2 °F

  • Highest 6 September, 2025

    92.7 °F

Climate (2020–Present)

Fort Belvoir (4.3 miles)

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  • Average Low 2020–2025

    47.8 °F

  • Average 2020–2025

    58.1 °F

  • Average High 2020–2025

    68.3 °F
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