Flat Lake Weather Forecast

    • 37
    • 64

    Increasing Clouds

    • 34
    • 47

    Rain Showers

    • 34
    • 49

    Rain Showers Likely

    • 32
    • 52

    Mostly Cloudy

    • 39
    • 63

    Partly Sunny

    • 42
    • 67

    Mostly Cloudy

Today 16 May McHenry

Sunny. Highs in the lower 60s. North Winds 10 to 15 Mph with Gusts up to 25 Mph.

Tonight 16 May McHenry

Mostly cloudy. A chance of Showers after midnight. Lows in the upper 30s. East Winds 15 to 20 Mph with Gusts up to 30 Mph. Chance of rain 30 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Flat Lake Temperature Statistics

May Temperature

Harvey Municipal Airport (22.4 miles)

  • Lowest 7 May, 2026

    23 °F

  • Average May

    51.4 °F

  • Highest 11 May, 2026

    80.6 °F

Climate (2021–Present)

Harvey Municipal Airport (22.4 miles)

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  • Average Low 2021–2026

    30.3 °F

  • Average 2021–2026

    41.2 °F

  • Average High 2021–2026

    51.9 °F
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