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 NW 5 mph
Barometer 29.75 in (1007.4 mb)
Dewpoint 33°F (1°C)
Visibility 9.00 mi
Wind Chill29°F (-2°C)
Last update 21 Feb 2:56 am EST
Extended Forecast for

Port Jefferson NY

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

  • Overnight

    Overnight: A slight chance of rain and snow before 4am, then a slight chance of snow. Mostly cloudy, with a low around 31. West wind around 5 mph. Chance of precipitation is 20%.

    Low: 31 °F

    Slight Chance
    Rain/Snow

  • Saturday

    Saturday: Mostly sunny, with a high near 42. West wind 3 to 6 mph.

    High: 42 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: A slight chance of rain and snow before 1am, then a chance of snow after 4am. Mostly cloudy, with a low around 31. Wind chill values between 25 and 30. Calm wind becoming east 5 to 7 mph after midnight. Chance of precipitation is 40%.

    Low: 31 °F

    Slight Chance
    Rain/Snow
    then Chance
    Snow

  • Sunday

    Sunday: Snow likely, mainly after 10am. Cloudy, with a high near 34. Wind chill values between 20 and 25. East wind 9 to 18 mph, with gusts as high as 28 mph. Chance of precipitation is 70%. New snow accumulation of 1 to 2 inches possible.

    High: 34 °F

    Snow Likely

  • Sunday Night

    Sunday Night: Snow. The snow could be heavy at times. Areas of blowing snow. Low around 30. Windy, with a north wind 24 to 34 mph. Chance of precipitation is 90%. New snow accumulation of 7 to 11 inches possible.

    Low: 30 °F

    Heavy Snow
    and Areas
    Blowing Snow

  • Monday

    Monday: Snow. The snow could be heavy at times. Areas of blowing snow. High near 33. Windy. Chance of precipitation is 90%. New snow accumulation of 4 to 8 inches possible.

    High: 33 °F

    Heavy Snow
    and Areas
    Blowing Snow

  • Monday Night

    Monday Night: Cloudy, then gradually becoming partly cloudy, with a low around 23. Blustery.

    Low: 23 °F

    Mostly Cloudy
    and Blustery
    then Mostly
    Cloudy

  • Tuesday

    Tuesday: Mostly sunny, with a high near 32.

    High: 32 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 20.

    Low: 20 °F

    Mostly Cloudy

Detailed Forecast

Overnight
A slight chance of rain and snow before 4am, then a slight chance of snow. Mostly cloudy, with a low around 31. West wind around 5 mph. Chance of precipitation is 20%.
Saturday
Mostly sunny, with a high near 42. West wind 3 to 6 mph.
Saturday Night
A slight chance of rain and snow before 1am, then a chance of snow after 4am. Mostly cloudy, with a low around 31. Wind chill values between 25 and 30. Calm wind becoming east 5 to 7 mph after midnight. Chance of precipitation is 40%.
Sunday
Snow likely, mainly after 10am. Cloudy, with a high near 34. Wind chill values between 20 and 25. East wind 9 to 18 mph, with gusts as high as 28 mph. Chance of precipitation is 70%. New snow accumulation of 1 to 2 inches possible.
Sunday Night
Snow. The snow could be heavy at times. Areas of blowing snow. Low around 30. Windy, with a north wind 24 to 34 mph. Chance of precipitation is 90%. New snow accumulation of 7 to 11 inches possible.
Monday
Snow. The snow could be heavy at times. Areas of blowing snow. High near 33. Windy. Chance of precipitation is 90%. New snow accumulation of 4 to 8 inches possible.
Monday Night
Cloudy, then gradually becoming partly cloudy, with a low around 23. Blustery.
Tuesday
Mostly sunny, with a high near 32.
Tuesday Night
Mostly cloudy, with a low around 20.
Wednesday
A chance of rain and snow before 1pm, then a chance of rain. Mostly cloudy, with a high near 37. Chance of precipitation is 30%.
Wednesday Night
A 50 percent chance of rain. Mostly cloudy, with a low around 31.
Thursday
A 50 percent chance of rain. Mostly cloudy, with a high near 41.
Thursday Night
A 50 percent chance of rain. Mostly cloudy, with a low around 29.
Friday
A 30 percent chance of rain. Mostly sunny, with a high near 40.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Port Jefferson NY
 40.93°N 73.06°W (Elev. 161 ft)
Last Update:
3:41 am EST Feb 21, 2026
Forecast Valid:
3am EST Feb 21, 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