Lake Forest Weather Forecast

    • 54
    • 72

    Rain Showers Likely

    • 53
    • 67

    Chance Rain Showers

    • 53
    • 65

    Rain Showers Likely

    • 51
    • 65

    Rain Showers Likely

    • 50
    • 67

    Mostly Cloudy

    • 50
    • 70

    Partly Sunny

Today 20 Sep Summit

Patchy fog in the morning. Showers likely in the Morning, then Showers likely with a slight chance of Thunderstorms in the afternoon. Humid with Highs in the lower 70s. West Winds around 5 Mph, becoming north in the afternoon. Chance of rain 70 percent.

Tonight 20 Sep Summit

A slight chance of Thunderstorms in the evening. Mostly cloudy with a slight chance of Showers. Lows in the mid 50s. Northeast Winds 5 to 10 Mph with Gusts up to 20 Mph. Chance of rain 20 percent.

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  • Temperature Forecast NOAA

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Lake Forest Temperature Statistics

September Temperature

Portage County Airport (11.2 miles)

  • Lowest 14 September, 2026

    50 °F

  • Average September

    69.6 °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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