Sister Island Weather Forecast

    • 56
    • 70

    Rain

    • 54
    • 66

    Partly Sunny

    • 56
    • 69

    Mostly Sunny

    • 60
    • 72

    Mostly Sunny

    • 60
    • 74

    Mostly Sunny

    • 58
    • 70

    Partly Sunny

Today 31 Jul Coastal Cumberland

Rain. Highs in the mid 70s. Light and variable Winds. Chance of rain 90 percent.

Tonight 31 Jul Coastal Cumberland

Rain. Patchy fog. Lows in the mid 50s. Light and variable Winds. Chance of rain 90 percent.

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Sister Island Temperature Statistics

July Temperature

Portland, Portland International Jetport (17.4 miles)

  • Lowest 22 July, 2025

    52.6 °F

  • Average July

    71.6 °F

  • Highest 6 July, 2025

    92.6 °F

Climate (2020–Present)

Portland, Portland International Jetport (17.4 miles)

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  • Average Low 2020–2025

    40.6 °F

  • Average 2020–2025

    49 °F

  • Average High 2020–2025

    57.4 °F
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