Chatham Harbor Weather Forecast

    • 61
    • 72

    Slight Chance Thunderstorms

    • 54
    • 73

    Mostly Sunny

    • 49
    • 66

    Mostly Sunny

    • 56
    • 67

    Partly Sunny

    • 60
    • 70

    Partly Sunny

    • 61
    • 72

    Partly Sunny

Today 18 Sep Barnstable

Mostly cloudy with a chance of Showers in the Morning, then mostly sunny in the afternoon. Patchy fog in the morning. Humid with Highs in the lower 70s. Northeast Winds around 5 Mph, becoming northwest in the afternoon. Chance of rain 50 percent.

Tonight 18 Sep Barnstable

Showers likely with a slight chance of Thunderstorms. Patchy fog. Near steady temperature in the lower 60s. East Winds around 5 Mph. Chance of rain 60 percent.

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Chatham Harbor Temperature Statistics

September Temperature

Chatham, Chatham Municipal Airport (1.9 miles)

  • Lowest 13 September, 2025

    46.9 °F

  • Average September

    64.6 °F

  • Highest 6 September, 2025

    79 °F

Climate (2020–Present)

Chatham, Chatham Municipal Airport (1.9 miles)

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  • Average Low 2020–2025

    47.7 °F

  • Average 2020–2025

    54 °F

  • Average High 2020–2025

    60.1 °F
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