Sister Island Weather Forecast

    • 29
    • 41

    Decreasing Clouds

    • 40
    • 46

    Rain

    • 25
    • 53

    Rain

    • 30
    • 36

    Chance Rain/Snow

    • 21
    • 42

    Slight Chance Rain

    • 16
    • 30

    Partly Sunny

Today 17 Dec Coastal Cumberland

Partly sunny. Highs around 40. Southwest Winds 10 to 15 Mph with Gusts up to 30 Mph.

Tonight 17 Dec Coastal Cumberland

Mostly clear. Lows in the lower 20s. West Winds around 10 Mph with Gusts up to 25 Mph in the Evening, becoming light and variable.

Graph Plots Open in Graphs

  • Temperature Forecast NOAA

  • Temperature Real-Time

Sister Island Temperature Statistics

December Temperature

Portland, Portland International Jetport (17.4 miles)

  • Lowest 9 December, 2025

    -0.9 °F

  • Average December

    23.9 °F

  • Highest 1 December, 2025

    39 °F

Climate (2020–Present)

Portland, Portland International Jetport (17.4 miles)

Take a look at our website widgetsAvailable free! Find Out More

  • Average Low 2020–2025

    40.4 °F

  • Average 2020–2025

    48.9 °F

  • Average High 2020–2025

    57.3 °F
Get WillyWeather+ to remove ads