Herndon Weather Forecast

    • 51
    • 62

    Chance Rain

    • 48
    • 64

    Partly Sunny

    • 52
    • 68

    Partly Sunny

    • 54
    • 71

    Partly Sunny

    • 54
    • 70

    Partly Sunny

    • 54
    • 72

    Partly Sunny

Today 23 Sep Eastern Loudoun

Cloudy. Showers Likely, mainly in the morning. Highs in the lower 60s. Northeast Winds around 10 Mph with Gusts up to 25 Mph. Chance of rain 70 percent.

Tonight 23 Sep Eastern Loudoun

Mostly cloudy. A slight chance of Showers in the evening. Lows in the lower 50s. Northeast Winds 5 to 10 Mph with Gusts up to 20 Mph. Chance of rain 20 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Herndon Temperature Statistics

September Temperature

Washington/Dulles International Airport, DC (4.3 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 (4.3 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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