Copco Lake Weather Forecast

    • 57
    • 87

    Increasing Clouds

    • 57
    • 84

    Slight Chance Thunderstorms

    • 53
    • 83

    Mostly Sunny

    • 53
    • 82

    Sunny

    • 56
    • 87

    Mostly Sunny

    • 53
    • 81

    Chance Rain Showers

Today 18 Sep North Central and Southeast Siskiyou County

Sunny in the Morning, then partly cloudy with a 20 percent chance of Thunderstorms in the afternoon. Highs in the mid 70s to mid 80s. Northeast Winds around 5 Mph shifting to the southeast late in the afternoon.

Tonight 18 Sep North Central and Southeast Siskiyou County

Mostly cloudy. Slight chance of Thunderstorms in the Evening, then slight chance of Showers after midnight. Lows in the lower 50s to lower 60s. West Winds 5 to 10 Mph. Chance of precipitation 20 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Copco Lake Temperature Statistics

September Temperature

Montague Siskiyou County Airport (16.2 miles)

  • Lowest 15 September, 2025

    44.1 °F

  • Average September

    68.2 °F

  • Highest 1 September, 2025

    95 °F

Climate (2020–Present)

Montague Siskiyou County Airport (16.2 miles)

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  • Average Low 2020–2025

    39.6 °F

  • Average 2020–2025

    54.2 °F

  • Average High 2020–2025

    69 °F
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