Castle Island Weather Forecast

    • 50
    • 56

    Rain Showers

    • 50
    • 51

    Rain Showers Likely

    • 56
    • 72

    Mostly Sunny

    • 54
    • 75

    Partly Sunny

    • 55
    • 68

    Partly Sunny

    • 59
    • 78

    Partly Sunny

Today 14 May Suffolk

Mostly cloudy. A chance of Showers in the Morning, then Showers with a chance of Thunderstorms in the afternoon. Highs in the lower 60s. East Winds 10 to 15 Mph. Chance of rain 90 percent.

Tonight 14 May Suffolk

Showers with a chance of Thunderstorms in the Evening, then Showers likely after midnight. Patchy fog. Lows in the upper 40s. Northeast Winds 5 to 10 Mph. Chance of rain 90 percent.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Castle Island Temperature Statistics

May Temperature

Boston, Logan International Airport (1.2 miles)

  • Lowest 9 May, 2026

    42.7 °F

  • Average May

    57.3 °F

  • Highest 5 May, 2026

    79.6 °F

Climate (2021–Present)

Boston, Logan International Airport (1.2 miles)

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  • Average Low 2021–2026

    46.7 °F

  • Average 2021–2026

    53.6 °F

  • Average High 2021–2026

    61 °F
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