Sumner Lake Weather Forecast

    • 54
    • 66

    Partly Sunny

    • 51
    • 57

    Partly Sunny

    • 51
    • 56

    Partly Sunny

    • 55
    • 58

    Chance Rain Showers

    • 55
    • 60

    Slight Chance Thunderstorms

    • 54
    • 60

    Chance Rain Showers

Today 17 Sep Keweenaw

Mostly sunny. Highs in the mid 70s. Temperature falling into the upper 60s this afternoon. Northwest Winds 5 to 10 Mph.

Tonight 17 Sep Keweenaw

Patchy fog in the evening. Partly cloudy. Lows around 54. North Winds 5 to 10 Mph, becoming northeast with Gusts up to 20 Mph after midnight.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Sumner Lake Temperature Statistics

September Temperature

Copper Harbor (53.4 miles)

  • Lowest 4 September, 2025

    46.9 °F

  • Average September

    58.8 °F

  • Highest 1 September, 2025

    75.9 °F

Climate (2020–Present)

Copper Harbor (53.4 miles)

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  • Average Low 2020–2025

    38.5 °F

  • Average 2020–2025

    44.7 °F

  • Average High 2020–2025

    50.9 °F
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