Grand River Weather Forecast

    • 61
    • 78

    Rain Showers Likely

    • 58
    • 77

    Decreasing Clouds

    • 60
    • 76

    Chance Rain Showers

    • 61
    • 76

    Chance Thunderstorms

    • 59
    • 80

    Chance Rain Showers

    • 57
    • 73

    Chance Rain Showers

    • 55
    • 73

    Slight Chance Rain Showers

Today 18 Sep Decatur

Showers likely with a chance of Thunderstorms. Near steady temperature in the mid 70s. Southwest Winds around 5 Mph. Chance of rain 70 percent.

Tonight 18 Sep Decatur

Mostly cloudy. Showers likely with a chance of Thunderstorms this Evening, then a chance of Showers with a slight chance of Thunderstorms after midnight. Patchy fog after midnight. Lows in the lower 60s. South Winds around 5 Mph. Chance of rain 60 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Grand River Temperature Statistics

September Temperature

Lamoni, Lamoni Municipal Airport (13 miles)

  • Lowest 7 September, 2025

    43 °F

  • Average September

    68.5 °F

  • Highest 12 September, 2025

    93.9 °F

Climate (2020–Present)

Lamoni, Lamoni Municipal Airport (13 miles)

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  • Average Low 2020–2025

    43.2 °F

  • Average 2020–2025

    53.1 °F

  • Average High 2020–2025

    63.1 °F
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