Big Sioux River Corridor Weather Forecast

    • 61
    • 76

    Rain Showers Likely

    • 56
    • 76

    Chance Rain Showers

    • 58
    • 73

    Chance Rain Showers

    • 59
    • 78

    Chance Rain Showers

    • 60
    • 80

    Slight Chance Thunderstorms

    • 55
    • 81

    Slight Chance Thunderstorms

    • 54
    • 76

    Mostly Sunny

Today 17 Sep Plymouth

Mostly cloudy. A chance of Showers and Thunderstorms Early, then Showers and Thunderstorms likely. Not as warm with Highs in the mid 70s. Northeast Winds 5 to 10 Mph, becoming southeast. Chance of rain 70 percent.

Tonight 17 Sep Plymouth

Mostly cloudy with a chance of Showers. A chance of Thunderstorms, mainly this evening. Lows in the lower 60s. Southeast Winds 5 to 10 Mph, becoming south after midnight. Chance of rain 50 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Big Sioux River Corridor Temperature Statistics

September Temperature

Sioux City, Sioux Gateway Airport (19.3 miles)

  • Lowest 7 September, 2025

    37.9 °F

  • Average September

    65.1 °F

  • Highest 13 September, 2025

    91.9 °F

Climate (2020–Present)

Sioux City, Sioux Gateway Airport (19.3 miles)

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  • Average Low 2020–2025

    38.8 °F

  • Average 2020–2025

    50.7 °F

  • Average High 2020–2025

    62.6 °F
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