Rock Island Lakes Weather Forecast

    • 30
    • 43

    Becoming Sunny

    • 34
    • 54

    Partly Sunny

    • 37
    • 60

    Mostly Sunny

    • 39
    • 59

    Rain Showers Likely

    • 34
    • 52

    Rain Showers Likely

    • 35
    • 52

    Partly Sunny

    • 36
    • 56

    Mostly Sunny

Today 14 Sep Northwest Beaverhead County

Mostly sunny. Near steady temperature in the upper 40s. West Winds 10 to 15 Mph with Gusts to around 35 Mph.

Tonight 14 Sep Northwest Beaverhead County

Mostly clear. Lows in the lower 30s. Northwest Winds up to 10 Mph shifting to the south after midnight. Gusts up to 25 Mph.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Rock Island Lakes Temperature Statistics

September Temperature

Salmon, Lemhi County Airport (15.5 miles)

  • Lowest 8 September, 2026

    37.9 °F

  • Average September

    58.9 °F

  • Highest 10 September, 2026

    82.9 °F

Climate (2021–2026)

Salmon, Lemhi County Airport (15.5 miles)

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  • Average Low 2021–2026

    33.1 °F

  • Average 2021–2026

    46.1 °F

  • Average High 2021–2026

    59.1 °F
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