Sylvan Lake Weather Forecast

    • 47
    • 69

    Rain Showers

    • 46
    • 58

    Rain Showers Likely

    • 47
    • 71

    Slight Chance Rain Showers

    • 44
    • 64

    Chance Rain Showers

    • 43
    • 60

    Chance Thunderstorms

    • 44
    • 65

    Mostly Sunny

Today 13 Sep Central Black Hills

Partly cloudy this Morning, then mostly sunny with a slight chance of Showers and Thunderstorms this afternoon. Highs in the mid 70s. Southwest Winds 5 to 10 Mph. Chance of rain 20 percent.

Tonight 13 Sep Central Black Hills

Partly cloudy with a slight chance of Showers and Thunderstorms in the Evening, then mostly cloudy with Showers with a chance of Thunderstorms after midnight. Lows in the lower 50s. North Winds 5 to 10 Mph. Chance of rain 90 percent.

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  • Temperature Real-Time

Sylvan Lake Temperature Statistics

September Temperature

Custer, Custer County Airport (8.1 miles)

  • Lowest 6 September, 2025

    32 °F

  • Average September

    60.2 °F

  • Highest 11 September, 2025

    82.9 °F

Climate (2020–Present)

Custer, Custer County Airport (8.1 miles)

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  • Average Low 2020–2025

    33.1 °F

  • Average 2020–2025

    44.8 °F

  • Average High 2020–2025

    56.2 °F
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