North Sioux City Weather Forecast

    • 60
    • 79

    Chance Thunderstorms

    • 59
    • 80

    Chance Thunderstorms

    • 56
    • 76

    Chance Thunderstorms

    • 53
    • 75

    Mostly Sunny

    • 53
    • 77

    Mostly Sunny

    • 53
    • 79

    Mostly Sunny

Today 21 Sep Union

Mostly sunny. Highs around 80. South Winds 5 to 10 Mph.

Tonight 21 Sep Union

Partly cloudy. A slight chance of Showers and Thunderstorms in the evening. Lows in the upper 50s. South Winds 5 to 10 Mph. Chance of rain 20 percent.

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North Sioux City Temperature Statistics

September Temperature

Sioux City, Sioux Gateway Airport (9.9 miles)

  • Lowest 7 September, 2025

    37.9 °F

  • Average September

    65.7 °F

  • Highest 13 September, 2025

    91.9 °F

Climate (2020–Present)

Sioux City, Sioux Gateway Airport (9.9 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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