Big Trinity Lake Weather Forecast

    • 36
    • 58

    Sunny

    • 38
    • 61

    Sunny

    • 41
    • 64

    Mostly Sunny

    • 40
    • 64

    Partly Sunny

    • 37
    • 58

    Partly Sunny

    • 36
    • 56

    Mostly Sunny

Today 16 Sep Boise Mountains

Widespread fog this morning. Sunny. Highs 66 to 79.

Tonight 16 Sep Boise Mountains

Mostly clear. Patchy fog after midnight. Lows 34 to 49.

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  • Temperature Real-Time

Big Trinity Lake Temperature Statistics

September Temperature

Boise Air Terminal (40.4 miles)

  • Lowest 12 September, 2025

    55 °F

  • Average September

    74.2 °F

  • Highest 1 September, 2025

    100 °F

Climate (2020–Present)

Boise Air Terminal (40.4 miles)

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  • Average Low 2020–2025

    43.8 °F

  • Average 2020–2025

    54.5 °F

  • Average High 2020–2025

    65.8 °F
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