Flat Lake Weather Forecast

    • 53
    • 79

    Mostly Sunny

    • 53
    • 83

    Mostly Sunny

    • 55
    • 78

    Partly Sunny

    • 55
    • 78

    Mostly Cloudy

    • 54
    • 76

    Partly Sunny

    • 54
    • 76

    Partly Sunny

Today 26 Aug McHenry

Sunny. Highs around 80. Southwest Winds around 5 Mph.

Tonight 26 Aug McHenry

Clear. Lows in the upper 40s. South Winds around 5 Mph.

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Flat Lake Temperature Statistics

August Temperature

Harvey Municipal Airport (22.4 miles)

  • Lowest 23 August, 2025

    46.4 °F

  • Average August

    67.3 °F

  • Highest 7 August, 2025

    87.8 °F

Climate (2020–Present)

Harvey Municipal Airport (22.4 miles)

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  • Average Low 2020–2025

    30.1 °F

  • Average 2020–2025

    41.1 °F

  • Average High 2020–2025

    51.8 °F
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