Olsons Bay Weather Forecast

    • 49
    • 62

    Mostly Cloudy

    • 47
    • 62

    Partly Sunny

    • 48
    • 64

    Partly Sunny

    • 49
    • 65

    Mostly Cloudy

    • 49
    • 67

    Mostly Cloudy

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    Mostly Cloudy

Today 21 Sep Jefferson

Mostly cloudy. Highs in the lower 60s. Northeast Winds 10 to 15 Mph.

Tonight 21 Sep Jefferson

Mostly cloudy. Slight chance of Sprinkles in the evening. Slight chance of Sprinkles after midnight. Lows in the upper 40s. Northeast Winds 5 to 15 Mph.

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Olsons Bay Temperature Statistics

September Temperature

Janesville-Rock County (17.4 miles)

  • Lowest 14 September, 2026

    42.8 °F

  • Average September

    67.3 °F

  • Highest 1 September, 2026

    91.4 °F

Climate (2021–2026)

Janesville-Rock County (17.4 miles)

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  • Average Low 2021–2026

    40.4 °F

  • Average 2021–2026

    48.7 °F

  • Average High 2021–2026

    60.2 °F
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