Great Diamond Island Weather Forecast

    • 54
    • 59

    Increasing Clouds

    • 42
    • 61

    Mostly Sunny

    • 37
    • 51

    Mostly Sunny

    • 42
    • 54

    Mostly Sunny

    • 44
    • 60

    Partly Sunny

    • 44
    • 54

    Chance Rain Showers

Today 29 Oct Coastal Cumberland

Mostly sunny. Highs in the mid 60s. Southwest Winds 10 to 15 Mph with Gusts up to 25 Mph.

Tonight 29 Oct Coastal Cumberland

Mostly clear in the Evening, then mostly cloudy with a slight chance of Showers after midnight. Lows in the upper 40s. Southwest Winds 10 to 15 Mph with Gusts up to 25 Mph. Chance of rain 20 percent.

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Great Diamond Island Temperature Statistics

October Temperature

Portland, Portland International Jetport (5 miles)

  • Lowest 18 October, 2026

    27.6 °F

  • Average October

    51.3 °F

  • Highest 2 October, 2026

    83.6 °F

Climate (2021–2026)

Portland, Portland International Jetport (5 miles)

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  • Average Low 2021–2026

    39.9 °F

  • Average 2021–2026

    48.7 °F

  • Average High 2021–2026

    57.3 °F
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