Jefferson Weather Forecast

    • 62
    • 86

    Chance Rain Showers

    • 64
    • 87

    Mostly Sunny

    • 61
    • 86

    Mostly Cloudy

    • 57
    • 77

    Chance Thunderstorms

    • 55
    • 75

    Chance Rain Showers

    • 53
    • 75

    Partly Sunny

Today 14 Sep Union

Partly sunny. A chance of Showers with a slight chance of Thunderstorms in the afternoon. Humid with Highs in the mid 80s. South Winds 10 to 15 Mph with Gusts up to 25 Mph. Chance of rain 30 percent.

Tonight 14 Sep Union

Mostly cloudy with a chance of Showers and Thunderstorms in the Evening, then partly cloudy with a slight chance of Showers and Thunderstorms after midnight. Humid with Lows in the lower 60s. South Winds 10 to 15 Mph with Gusts up to 25 Mph. Chance of rain 40 percent.

Graph Plots Open in Graphs

  • Temperature Forecast NOAA

  • Temperature Real-Time

Jefferson Temperature Statistics

September Temperature

Sioux City, Sioux Gateway Airport (16.2 miles)

  • Lowest 7 September, 2025

    37.9 °F

  • Average September

    61.9 °F

  • Highest 11 September, 2025

    84.9 °F

Climate (2020–Present)

Sioux City, Sioux Gateway Airport (16.2 miles)

Take a look at our website widgetsAvailable free! Find Out More

  • Average Low 2020–2025

    38.8 °F

  • Average 2020–2025

    50.7 °F

  • Average High 2020–2025

    62.6 °F
Get WillyWeather+ to remove ads