Big Flat Weather Forecast

    • 59
    • 64

    Mostly Cloudy

    • 58
    • 60

    Mostly Cloudy

    • 57
    • 60

    Partly Sunny

    • 58
    • 64

    Mostly Sunny

    • 59
    • 65

    Mostly Sunny

    • 59
    • 64

    Chance Rain

Today 18 Sep Southwestern Humboldt

Mostly cloudy. Highs 74 to 89. North wind 5 to 15 Mph.

Tonight 18 Sep Southwestern Humboldt

Mostly cloudy. Slight chance of rain Showers overnight. Lows 53 to 63. In the Valleys, southwest wind around 10 Mph shifting to the east overnight. At higher Elevation, southeast wind around 5 Mph increasing to east around 15 Mph overnight.

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  • Temperature Real-Time

Big Flat Temperature Statistics

September Temperature

Fortuna Rohnerville Airport (29.2 miles)

  • Lowest 7 September, 2025

    51.8 °F

  • Average September

    59 °F

  • Highest 14 September, 2025

    71.6 °F

Climate (2020–Present)

Fortuna Rohnerville Airport (29.2 miles)

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  • Average Low 2020–2025

    45.1 °F

  • Average 2020–2025

    51.2 °F

  • Average High 2020–2025

    59.5 °F
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