National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce
Current conditions at

Islip, Long Island Mac Arthur Airport (KISP)

Lat: 40.79°NLon: 73.1°WElev: 98ft.

A Few Clouds

74°F

23°C

Humidity 50%
Wind Speed W 5 mph
Barometer 30.13 in (1020.3 mb)
Dewpoint 54°F (12°C)
Visibility 10.00 mi
Last update 7 Sep 6:56 pm EDT
Extended Forecast for

Port Jefferson NYSimilar City Names

  • Tonight

    Tonight: Partly cloudy, with a low around 62. Northwest wind around 6 mph.

    Low: 62 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Sunny, with a high near 80. West wind around 6 mph.

    High: 80 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 67. Southwest wind around 5 mph becoming calm after midnight.

    Low: 67 °F

    Partly Cloudy

  • Wednesday

    Wednesday: Mostly sunny, with a high near 81. Light southwest wind becoming south 6 to 11 mph in the morning.

    High: 81 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 71. Southwest wind around 17 mph.

    Low: 71 °F

    Partly Cloudy

  • Thursday

    Thursday: A 30 percent chance of showers after 2pm. Mostly sunny, with a high near 83.

    High: 83 °F

    Mostly Sunny
    then Chance
    Showers

  • Thursday Night

    Thursday Night: A 30 percent chance of showers before 8pm. Mostly cloudy, with a low around 67.

    Low: 67 °F

    Chance
    Showers then
    Mostly Cloudy

  • Friday

    Friday: Sunny, with a high near 76.

    High: 76 °F

    Sunny

  • Friday Night

    Friday Night: Mostly clear, with a low around 64.

    Low: 64 °F

    Mostly Clear

Detailed Forecast

Tonight
Partly cloudy, with a low around 62. Northwest wind around 6 mph.
Tuesday
Sunny, with a high near 80. West wind around 6 mph.
Tuesday Night
Partly cloudy, with a low around 67. Southwest wind around 5 mph becoming calm after midnight.
Wednesday
Mostly sunny, with a high near 81. Light southwest wind becoming south 6 to 11 mph in the morning.
Wednesday Night
Partly cloudy, with a low around 71. Southwest wind around 17 mph.
Thursday
A 30 percent chance of showers after 2pm. Mostly sunny, with a high near 83.
Thursday Night
A 30 percent chance of showers before 8pm. Mostly cloudy, with a low around 67.
Friday
Sunny, with a high near 76.
Friday Night
Mostly clear, with a low around 64.
Saturday
Mostly sunny, with a high near 76.
Saturday Night
Partly cloudy, with a low around 65.
Sunday
Mostly sunny, with a high near 78.
Sunday Night
Partly cloudy, with a low around 66.
Monday
Mostly sunny, with a high near 77.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Port Jefferson NYSimilar City Names
 40.95°N 73.05°W (Elev. 151 ft)
Last Update:
2:19 pm EDT Sep 7, 2026
Forecast Valid:
7pm EDT Sep 7, 2026-6pm EDT Sep 14, 2026
 
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Additional Resources

Radar & Satellite Image

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Hourly Weather Forecast

National Digital Forecast Database

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation