Grass Lake Weather Forecast

    • 50
    • 69

    Rain

    • 51
    • 61

    Rain

    • 49
    • 67

    Mostly Cloudy

    • 49
    • 69

    Partly Sunny

    • 52
    • 76

    Mostly Sunny

    • 53
    • 79

    Mostly Sunny

    • 54
    • 80

    Mostly Sunny

Today 12 Sep Foothills and Valleys of Pierce and Southern King Counties

Cloudy. Highs near 70. Light wind.

Tonight 12 Sep Foothills and Valleys of Pierce and Southern King Counties

A chance of rain in the Evening, then rain likely late in the evening. Rain after midnight. Patchy fog after midnight. Rainfall Amounts a half inch to one inch possible. Lows near 50. Light wind.

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  • Temperature Real-Time

Grass Lake Temperature Statistics

September Temperature

Renton Municipal Airport (12.4 miles)

  • Lowest 6 September, 2026

    51.1 °F

  • Average September

    62.4 °F

  • Highest 9 September, 2026

    79 °F

Climate (2021–2026)

Renton Municipal Airport (12.4 miles)

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  • Average Low 2021–2026

    47.4 °F

  • Average 2021–2026

    54.7 °F

  • Average High 2021–2026

    62.2 °F
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