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.

Fog/Mist

25°F

-4°C

Humidity 96%
Wind Speed Calm
Barometer 30.12 in (1020.1 mb)
Dewpoint 24°F (-4°C)
Visibility 5.00 mi
Last update 28 Feb 2:56 am EST
Extended Forecast for

Port Jefferson NY

  • Overnight

    Overnight: Partly cloudy, with a low around 30. Light south wind.

    Low: 30 °F

    Partly Cloudy

  • Saturday

    Saturday: Mostly sunny, with a high near 42. South wind 3 to 8 mph.

    High: 42 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: Partly cloudy, with a low around 30. Light and variable wind becoming north 5 to 7 mph after midnight.

    Low: 30 °F

    Partly Cloudy

  • Sunday

    Sunday: Snow likely, mainly between 10am and 4pm. Mostly sunny through mid morning, then becoming cloudy, with a high near 35. Wind chill values between 25 and 30. North wind 8 to 10 mph. Chance of precipitation is 60%. New snow accumulation of less than one inch possible.

    High: 35 °F

    Snow Likely

  • Sunday Night

    Sunday Night: A 30 percent chance of snow before 7pm. Mostly clear, with a low around 18. North wind around 16 mph.

    Low: 18 °F

    Chance Snow
    then Mostly
    Clear

  • Monday

    Monday: Sunny, with a high near 27.

    High: 27 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 22.

    Low: 22 °F

    Mostly Clear

  • Tuesday

    Tuesday: A 50 percent chance of rain after 1pm. Mostly cloudy, with a high near 40.

    High: 40 °F

    Mostly Cloudy
    then Chance
    Rain

  • Tuesday Night

    Tuesday Night: Rain. Low around 37. Chance of precipitation is 90%.

    Low: 37 °F

    Rain

Detailed Forecast

Overnight
Partly cloudy, with a low around 30. Light south wind.
Saturday
Mostly sunny, with a high near 42. South wind 3 to 8 mph.
Saturday Night
Partly cloudy, with a low around 30. Light and variable wind becoming north 5 to 7 mph after midnight.
Sunday
Snow likely, mainly between 10am and 4pm. Mostly sunny through mid morning, then becoming cloudy, with a high near 35. Wind chill values between 25 and 30. North wind 8 to 10 mph. Chance of precipitation is 60%. New snow accumulation of less than one inch possible.
Sunday Night
A 30 percent chance of snow before 7pm. Mostly clear, with a low around 18. North wind around 16 mph.
Monday
Sunny, with a high near 27.
Monday Night
Mostly clear, with a low around 22.
Tuesday
A 50 percent chance of rain after 1pm. Mostly cloudy, with a high near 40.
Tuesday Night
Rain. Low around 37. Chance of precipitation is 90%.
Wednesday
A 30 percent chance of rain before 1pm. Mostly cloudy, with a high near 43.
Wednesday Night
A 30 percent chance of rain. Mostly cloudy, with a low around 36.
Thursday
A 40 percent chance of rain. Cloudy, with a high near 45.
Thursday Night
A 50 percent chance of rain. Cloudy, with a low around 41.
Friday
A 30 percent chance of rain. Cloudy, with a high near 46.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Port Jefferson NY
 40.96°N 73.08°W (Elev. 3 ft)
Last Update:
12:55 am EST Feb 28, 2026
Forecast Valid:
3am EST Feb 28, 2026-6pm EST Mar 6, 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