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

Hazardous Weather Conditions

Current conditions at

Islip, Long Island Mac Arthur Airport (KISP)

Lat: 40.79°NLon: 73.1°WElev: 98ft.

Fair

40°F

4°C

Humidity 83%
Wind Speed W 9 mph
Barometer 29.78 in (1008.5 mb)
Dewpoint 35°F (2°C)
Visibility 10.00 mi
Wind Chill34°F (1°C)
Last update 14 Mar 3:56 am EDT
Extended Forecast for

Port Jefferson NY

  • Today

    Today: Sunny, with a high near 47. Breezy, with a west wind 11 to 16 mph increasing to 20 to 25 mph in the afternoon. Winds could gust as high as 41 mph.

    High: 47 °F

    Sunny and
    Breezy

  • Tonight

    Tonight: Increasing clouds, with a low around 31. West wind 5 to 15 mph.

    Low: 31 °F

    Increasing
    Clouds

  • Sunday

    Sunday: Partly sunny, with a high near 46. Northeast wind 5 to 10 mph becoming southeast in the afternoon.

    High: 46 °F

    Partly Sunny

  • Sunday Night

    Sunday Night: Rain after 2am. Temperature falling to near 41 by 8pm, then rising to around 48 during the remainder of the night. Southeast wind 7 to 11 mph, with gusts as high as 21 mph. Chance of precipitation is 80%. New precipitation amounts between a quarter and half of an inch possible.

    Low: 41 °F⇑

    Mostly Cloudy
    then Rain

  • Monday

    Monday: Rain and possibly a thunderstorm. Some of the storms could produce heavy rainfall. High near 58. Breezy, with a south wind 16 to 20 mph, with gusts as high as 40 mph. Chance of precipitation is 100%. New rainfall amounts between a half and three quarters of an inch possible.

    High: 58 °F

    Heavy Rain
    and Breezy

  • Monday Night

    Monday Night: Rain before 5am, then a chance of rain and snow. The rain could be heavy at times. Some thunder is also possible. Low around 34. Windy. Chance of precipitation is 100%. Little or no snow accumulation expected.

    Low: 34 °F

    Heavy Rain
    and Windy
    then
    Rain/Snow and
    Breezy

  • Tuesday

    Tuesday: A chance of rain and snow before 8am. Mostly cloudy, then gradually becoming sunny, with a high near 43. Chance of precipitation is 30%.

    High: 43 °F

    Chance
    Rain/Snow
    then Mostly
    Sunny

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 24.

    Low: 24 °F

    Partly Cloudy

  • Wednesday

    Wednesday: Mostly sunny, with a high near 38.

    High: 38 °F

    Mostly Sunny

Detailed Forecast

Today
Sunny, with a high near 47. Breezy, with a west wind 11 to 16 mph increasing to 20 to 25 mph in the afternoon. Winds could gust as high as 41 mph.
Tonight
Increasing clouds, with a low around 31. West wind 5 to 15 mph.
Sunday
Partly sunny, with a high near 46. Northeast wind 5 to 10 mph becoming southeast in the afternoon.
Sunday Night
Rain after 2am. Temperature falling to near 41 by 8pm, then rising to around 48 during the remainder of the night. Southeast wind 7 to 11 mph, with gusts as high as 21 mph. Chance of precipitation is 80%. New precipitation amounts between a quarter and half of an inch possible.
Monday
Rain and possibly a thunderstorm. Some of the storms could produce heavy rainfall. High near 58. Breezy, with a south wind 16 to 20 mph, with gusts as high as 40 mph. Chance of precipitation is 100%. New rainfall amounts between a half and three quarters of an inch possible.
Monday Night
Rain before 5am, then a chance of rain and snow. The rain could be heavy at times. Some thunder is also possible. Low around 34. Windy. Chance of precipitation is 100%. Little or no snow accumulation expected.
Tuesday
A chance of rain and snow before 8am. Mostly cloudy, then gradually becoming sunny, with a high near 43. Chance of precipitation is 30%.
Tuesday Night
Partly cloudy, with a low around 24.
Wednesday
Mostly sunny, with a high near 38.
Wednesday Night
Mostly cloudy, with a low around 29.
Thursday
Mostly sunny, with a high near 44.
Thursday Night
Partly cloudy, with a low around 34.
Friday
Mostly sunny, with a high near 48.
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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:
3:09 am EDT Mar 14, 2026
Forecast Valid:
4am EDT Mar 14, 2026-6pm EDT Mar 20, 2026
 
Forecast Discussion
 
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Additional Resources

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Hourly Weather Forecast

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation