Lannon Lake Weather Forecast

    • 59
    • 71

    Chance Thunderstorms

    • 57
    • 67

    Rain Showers Likely

    • 55
    • 70

    Chance Rain Showers

    • 57
    • 77

    Chance Rain Showers

    • 55
    • 77

    Slight Chance Thunderstorms

    • 54
    • 72

    Mostly Sunny

Today 18 Sep Big Stone

Cloudy with a 50 percent chance of Thunderstorms. Highs in the lower 70s. East Winds 5 to 10 Mph, becoming southeast this afternoon.

Tonight 18 Sep Big Stone

Mostly cloudy with a slight chance of Thunderstorms. A chance of Showers in the Evening, then Showers likely after midnight. Lows around 60. East Winds around 5 Mph. Chance of rain 70 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Lannon Lake Temperature Statistics

September Temperature

Wheaton Municipal Airport (16.8 miles)

  • Lowest 7 September, 2025

    39.2 °F

  • Average September

    62.1 °F

  • Highest 14 September, 2025

    87.8 °F

Climate (2020–Present)

Wheaton Municipal Airport (16.8 miles)

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  • Average Low 2020–2025

    34.9 °F

  • Average 2020–2025

    44.8 °F

  • Average High 2020–2025

    54.5 °F
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