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.

Overcast

34°F

1°C

Humidity 97%
Wind Speed N 6 mph
Barometer 29.66 in (1004.5 mb)
Dewpoint 33°F (1°C)
Visibility 10.00 mi
Wind Chill29°F (-2°C)
Last update 20 Feb 10:56 pm EST
Extended Forecast for

Port Jefferson NY

Winter Storm Watch February 22, 06:00am until February 23, 06:00pm
Coastal Flood Watch February 23, 12:00am until February 23, 05:00am
Click here for hazard details and duration
Winter Storm Watch
Coastal Flood Watch

  • Tonight

    Tonight: A chance of rain before 1am, then a slight chance of rain and snow between 1am and 2am, then a slight chance of snow after 2am. Areas of fog before midnight. Otherwise, mostly cloudy, with a low around 34. West wind 6 to 9 mph. Chance of precipitation is 30%.

    Low: 34 °F

    Chance
    Rain/Snow and
    Areas Fog

  • Saturday

    Saturday: Mostly cloudy, then gradually becoming sunny, with a high near 41. West wind around 7 mph becoming north in the afternoon.

    High: 41 °F

    Decreasing
    Clouds

  • Saturday Night

    Saturday Night: A chance of rain before 10pm, then a chance of rain and snow. Mostly cloudy, with a low around 30. East wind 5 to 11 mph becoming south in the evening. Chance of precipitation is 40%.

    Low: 30 °F

    Chance
    Rain/Snow

  • Sunday

    Sunday: Snow likely, mainly after 1pm. Cloudy, with a high near 36. Wind chill values between 20 and 25. Breezy, with an east wind 18 to 24 mph, with gusts as high as 36 mph. Chance of precipitation is 60%. New snow accumulation of 1 to 3 inches possible.

    High: 36 °F

    Snow Likely
    and Breezy

  • Sunday Night

    Sunday Night: Snow. Areas of blowing snow. Low around 28. Windy, with a northeast wind 28 to 34 mph, with gusts as high as 46 mph. Chance of precipitation is 90%. New snow accumulation of 4 to 8 inches possible.

    Low: 28 °F

    Snow and
    Areas Blowing
    Snow

  • Monday

    Monday: Snow, mainly before 1pm. Areas of blowing snow before 4pm. High near 34. Windy. Chance of precipitation is 80%. New snow accumulation of 3 to 5 inches possible.

    High: 34 °F

    Snow and
    Areas Blowing
    Snow

  • Monday Night

    Monday Night: Mostly cloudy, with a low around 23. Blustery.

    Low: 23 °F

    Mostly Cloudy
    and Blustery

  • Tuesday

    Tuesday: Mostly sunny, with a high near 33.

    High: 33 °F

    Mostly Sunny

  • Tuesday Night

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

    Low: 24 °F

    Mostly Cloudy

Detailed Forecast

Tonight
A chance of rain before 1am, then a slight chance of rain and snow between 1am and 2am, then a slight chance of snow after 2am. Areas of fog before midnight. Otherwise, mostly cloudy, with a low around 34. West wind 6 to 9 mph. Chance of precipitation is 30%.
Saturday
Mostly cloudy, then gradually becoming sunny, with a high near 41. West wind around 7 mph becoming north in the afternoon.
Saturday Night
A chance of rain before 10pm, then a chance of rain and snow. Mostly cloudy, with a low around 30. East wind 5 to 11 mph becoming south in the evening. Chance of precipitation is 40%.
Sunday
Snow likely, mainly after 1pm. Cloudy, with a high near 36. Wind chill values between 20 and 25. Breezy, with an east wind 18 to 24 mph, with gusts as high as 36 mph. Chance of precipitation is 60%. New snow accumulation of 1 to 3 inches possible.
Sunday Night
Snow. Areas of blowing snow. Low around 28. Windy, with a northeast wind 28 to 34 mph, with gusts as high as 46 mph. Chance of precipitation is 90%. New snow accumulation of 4 to 8 inches possible.
Monday
Snow, mainly before 1pm. Areas of blowing snow before 4pm. High near 34. Windy. Chance of precipitation is 80%. New snow accumulation of 3 to 5 inches possible.
Monday Night
Mostly cloudy, with a low around 23. Blustery.
Tuesday
Mostly sunny, with a high near 33.
Tuesday Night
Mostly cloudy, with a low around 24.
Wednesday
A 30 percent chance of snow before 1pm. Mostly cloudy, with a high near 38.
Wednesday Night
A chance of rain and snow. Mostly cloudy, with a low around 35. Chance of precipitation is 50%.
Thursday
Rain likely. Mostly cloudy, with a high near 42. Chance of precipitation is 60%.
Thursday Night
A chance of rain and snow. Mostly cloudy, with a low around 32. Chance of precipitation is 40%.
Friday
Mostly sunny, with a high near 38.
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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:
5:24 pm EST Feb 20, 2026
Forecast Valid:
11pm EST Feb 20, 2026-6pm EST Feb 27, 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