Steffan Reservoir Weather Forecast

    • 46
    • 69

    Increasing Clouds

    • 44
    • 66

    Rain Showers

    • 49
    • 72

    Partly Sunny

    • 57
    • 82

    Mostly Sunny

    • 60
    • 87

    Mostly Sunny

    • 59
    • 86

    Partly Sunny

    • 59
    • 84

    Chance Thunderstorms

Today 21 May Knox

Mostly sunny. Near steady temperature in the upper 60s. Southeast Winds 15 to 20 Mph.

Tonight 21 May Knox

Cloudy. A chance of Showers in the Evening, then Showers with a slight chance of Thunderstorms after midnight. Lows in the mid 40s. Southeast Winds 15 to 20 Mph. Chance of rain 90 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Steffan Reservoir Temperature Statistics

May Temperature

Yankton, Chan Gurney Municipal Airport (11.2 miles)

  • Lowest 6 May, 2026

    30 °F

  • Average May

    58.2 °F

  • Highest 15 May, 2026

    88 °F

Climate (2021–Present)

Yankton, Chan Gurney Municipal Airport (11.2 miles)

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  • Average Low 2021–2026

    39.3 °F

  • Average 2021–2026

    50.5 °F

  • Average High 2021–2026

    61.8 °F
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