Mystic Weather Forecast

    • 41
    • 68

    Partly Sunny

    • 51
    • 65

    Chance Thunderstorms

    • 37
    • 73

    Mostly Sunny

    • 43
    • 68

    Chance Rain Showers

    • 42
    • 73

    Mostly Sunny

    • 45
    • 75

    Slight Chance Thunderstorms

Today 12 Sep Northern Black Hills

Partly cloudy. Highs in the mid 60s. South Winds 5 to 10 Mph. Gusts up to 20 Mph this afternoon.

Tonight 12 Sep Northern Black Hills

Partly cloudy. Lows in the lower 40s. Southeast Winds 5 to 10 Mph with Gusts up to 20 Mph.

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Mystic Temperature Statistics

September Temperature

Custer, Custer County Airport (23.6 miles)

  • Lowest 10 September, 2026

    43 °F

  • Average September

    66.8 °F

  • Highest 4 September, 2026

    86.6 °F

Climate (2021–2026)

Custer, Custer County Airport (23.6 miles)

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  • Average Low 2021–2026

    33.6 °F

  • Average 2021–2026

    45.4 °F

  • Average High 2021–2026

    57 °F
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