Lake Forest Weather Forecast

    • 66
    • 76

    Chance Thunderstorms

    • 58
    • 80

    Chance Rain Showers

    • 56
    • 79

    Mostly Sunny

    • 58
    • 80

    Partly Sunny

    • 65
    • 83

    Mostly Cloudy

    • 68
    • 88

    Chance Rain Showers

    • 58
    • 79

    Mostly Cloudy

Today 4 Sep Summit

Showers likely with a chance of Thunderstorms. Cooler. Near steady temperature in the upper 70s. West Winds around 5 Mph. Chance of rain 60 percent.

Tonight 4 Sep Summit

Mostly cloudy with a chance of Showers and Thunderstorms. Patchy fog after midnight. Lows in the mid 60s. North Winds around 5 Mph. Chance of rain 50 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Lake Forest Temperature Statistics

September Temperature

Portage County Airport (11.2 miles)

  • Lowest 1 September, 2026

    68.9 °F

  • Average September

    77.8 °F

  • Highest 2 September, 2026

    91 °F

Climate (2021–2026)

Portage County Airport (11.2 miles)

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  • Average Low 2021–2026

    40.5 °F

  • Average 2021–2026

    50 °F

  • Average High 2021–2026

    60 °F
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