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.

Fog/Mist

52°F

11°C

Humidity 97%
Wind Speed SW 14 G 30 mph
Barometer 29.83 in (1010.1 mb)
Dewpoint 51°F (11°C)
Visibility 0.50 mi
Wind Chill47°F (8°C)
Last update 5 Apr 10:56 am EDT
Extended Forecast for

Port Jefferson NY

  • Today

    Today: Rain and possibly a thunderstorm. High near 59. Southwest wind around 14 mph, with gusts as high as 24 mph. Chance of precipitation is 100%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

    High: 59 °F

    Rain

  • Tonight

    Tonight: Rain likely before 8pm. Cloudy during the early evening, then gradual clearing, with a low around 39. West wind 8 to 10 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

    Low: 39 °F

    Rain Likely
    then Mostly
    Clear

  • Monday

    Monday: Sunny, with a high near 53. West wind around 11 mph.

    High: 53 °F

    Sunny

  • Monday Night

    Monday Night: A 20 percent chance of rain. Partly cloudy, with a low around 39. Southwest wind around 6 mph.

    Low: 39 °F

    Slight Chance
    Rain

  • Tuesday

    Tuesday: A 20 percent chance of rain before 2pm. Mostly sunny, with a high near 51. West wind 8 to 14 mph.

    High: 51 °F

    Slight Chance
    Rain

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 30.

    Low: 30 °F

    Mostly Clear

  • Wednesday

    Wednesday: Sunny, with a high near 46.

    High: 46 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 35.

    Low: 35 °F

    Mostly Clear

  • Thursday

    Thursday: Mostly sunny, with a high near 53.

    High: 53 °F

    Mostly Sunny

Detailed Forecast

Today
Rain and possibly a thunderstorm. High near 59. Southwest wind around 14 mph, with gusts as high as 24 mph. Chance of precipitation is 100%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Tonight
Rain likely before 8pm. Cloudy during the early evening, then gradual clearing, with a low around 39. West wind 8 to 10 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.
Monday
Sunny, with a high near 53. West wind around 11 mph.
Monday Night
A 20 percent chance of rain. Partly cloudy, with a low around 39. Southwest wind around 6 mph.
Tuesday
A 20 percent chance of rain before 2pm. Mostly sunny, with a high near 51. West wind 8 to 14 mph.
Tuesday Night
Mostly clear, with a low around 30.
Wednesday
Sunny, with a high near 46.
Wednesday Night
Mostly clear, with a low around 35.
Thursday
Mostly sunny, with a high near 53.
Thursday Night
Partly cloudy, with a low around 43.
Friday
Mostly sunny, with a high near 62.
Friday Night
Partly cloudy, with a low around 46.
Saturday
Partly sunny, with a high near 61.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Port Jefferson NY
 40.93°N 73.06°W (Elev. 161 ft)
Last Update:
5:03 am EDT Apr 5, 2026
Forecast Valid:
11am EDT Apr 5, 2026-6pm EDT Apr 11, 2026
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation