Steffan Reservoir Weather Forecast

    • 54
    • 73

    Slight Chance Rain Showers

    • 58
    • 69

    Rain Showers

    • 56
    • 78

    Rain Showers

    • 55
    • 70

    Mostly Cloudy

    • 55
    • 70

    Slight Chance Thunderstorms

    • 57
    • 73

    Chance Rain Showers

Today 12 Sep Knox

Partly cloudy. Not as warm with Highs in the lower 70s. North Winds 10 to 15 Mph with Gusts up to 25 Mph.

Tonight 12 Sep Knox

Mostly clear in the Evening, then partly cloudy with a slight chance of Showers and Thunderstorms after midnight. Lows in the mid 50s. East Winds around 5 Mph. Chance of rain 20 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Steffan Reservoir Temperature Statistics

September Temperature

Yankton, Chan Gurney Municipal Airport (11.2 miles)

  • Lowest 9 September, 2026

    57 °F

  • Average September

    76.8 °F

  • Highest 4 September, 2026

    95 °F

Climate (2021–2026)

Yankton, Chan Gurney Municipal Airport (11.2 miles)

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  • Average Low 2021–2026

    39.4 °F

  • Average 2021–2026

    50.6 °F

  • Average High 2021–2026

    61.8 °F
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