Newcastle Weather Forecast

    • 52
    • 65

    Decreasing Clouds

    • 50
    • 69

    Partly Sunny

    • 55
    • 78

    Mostly Cloudy

    • 53
    • 73

    Slight Chance Rain

    • 50
    • 68

    Chance Rain

    • 47
    • 61

    Chance Rain

Today 10 May Foothills and Valleys of Central King County

Mostly cloudy. Highs in the mid 60s to lower 70s. Light wind.

Tonight 10 May Foothills and Valleys of Central King County

Mostly cloudy in the evening then becoming partly cloudy. Lows near 50. Light wind.

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  • Temperature Forecast NOAA

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Newcastle Temperature Statistics

May Temperature

Renton Municipal Airport (3.7 miles)

  • Lowest 1 May, 2026

    51.1 °F

  • Average May

    62.6 °F

  • Highest 3 May, 2026

    79 °F

Climate (2021–Present)

Renton Municipal Airport (3.7 miles)

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  • Average Low 2021–2026

    47.5 °F

  • Average 2021–2026

    54.7 °F

  • Average High 2021–2026

    62.3 °F
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