Castalia Weather Forecast

    • 62
    • 81

    Rain Showers Likely

    • 58
    • 74

    Rain Showers Likely

    • 60
    • 74

    Chance Thunderstorms

    • 60
    • 76

    Chance Thunderstorms

    • 58
    • 76

    Chance Rain Showers

    • 54
    • 72

    Slight Chance Thunderstorms

Today 18 Sep Winneshiek

Partly sunny with a chance of Showers. A chance of Thunderstorms this afternoon. Highs in the lower 80s. South Winds around 5 Mph. Chance of rain 30 percent.

Tonight 18 Sep Winneshiek

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

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  • Temperature Real-Time

Castalia Temperature Statistics

September Temperature

Decorah (11.8 miles)

  • Lowest 4 September, 2025

    41 °F

  • Average September

    63.2 °F

  • Highest 14 September, 2025

    86 °F

Climate (2020–Present)

Decorah (11.8 miles)

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  • Average Low 2020–2025

    39.3 °F

  • Average 2020–2025

    47.9 °F

  • Average High 2020–2025

    56.4 °F
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