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Current conditions at

Islip, Long Island Mac Arthur Airport (KISP)

Lat: 40.79°NLon: 73.1°WElev: 98ft.

Fog/Mist

58°F

14°C

Humidity 90%
Wind Speed W 3 mph
Barometer 29.80 in (1009.0 mb)
Dewpoint 55°F (13°C)
Visibility 3.00 mi
Last update 17 Mar 11:56 am EDT
Extended Forecast for

Port Jefferson NY

  • This Afternoon

    This Afternoon: Showers likely, mainly before 2pm. Cloudy, with a temperature falling to around 48 by 5pm. North wind 5 to 8 mph becoming northwest. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.

    High: 54 °F⇓

    Showers
    Likely

  • Tonight

    Tonight: A 30 percent chance of showers, mainly before 8pm. Mostly cloudy, with a low around 36. Northwest wind 11 to 13 mph.

    Low: 36 °F

    Chance
    Showers then
    Mostly Cloudy

  • Tuesday

    Tuesday: Partly sunny, then gradually becoming sunny, with a high near 54. Northwest wind 6 to 11 mph.

    High: 54 °F

    Becoming
    Sunny

  • Tuesday Night

    Tuesday Night: Clear, with a low around 40. Northwest wind around 5 mph becoming light and variable in the evening.

    Low: 40 °F

    Clear

  • Wednesday

    Wednesday: Mostly sunny, with a high near 55. East wind around 7 mph.

    High: 55 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 41.

    Low: 41 °F

    Mostly Cloudy

  • Thursday

    Thursday: A 30 percent chance of showers after 2pm. Mostly cloudy, with a high near 54.

    High: 54 °F

    Mostly Cloudy
    then Chance
    Showers

  • Thursday Night

    Thursday Night: Showers likely, mainly after 8pm. Mostly cloudy, with a low around 37. Chance of precipitation is 70%.

    Low: 37 °F

    Showers
    Likely

  • Friday

    Friday: Partly sunny, with a high near 45. Breezy.

    High: 45 °F

    Partly Sunny
    and Breezy

Detailed Forecast

This Afternoon
Showers likely, mainly before 2pm. Cloudy, with a temperature falling to around 48 by 5pm. North wind 5 to 8 mph becoming northwest. Chance of precipitation is 70%. New precipitation amounts of less than a tenth of an inch possible.
Tonight
A 30 percent chance of showers, mainly before 8pm. Mostly cloudy, with a low around 36. Northwest wind 11 to 13 mph.
Tuesday
Partly sunny, then gradually becoming sunny, with a high near 54. Northwest wind 6 to 11 mph.
Tuesday Night
Clear, with a low around 40. Northwest wind around 5 mph becoming light and variable in the evening.
Wednesday
Mostly sunny, with a high near 55. East wind around 7 mph.
Wednesday Night
Mostly cloudy, with a low around 41.
Thursday
A 30 percent chance of showers after 2pm. Mostly cloudy, with a high near 54.
Thursday Night
Showers likely, mainly after 8pm. Mostly cloudy, with a low around 37. Chance of precipitation is 70%.
Friday
Partly sunny, with a high near 45. Breezy.
Friday Night
Partly cloudy, with a low around 34. Breezy.
Saturday
Mostly sunny, with a high near 51.
Saturday Night
Mostly cloudy, with a low around 39.
Sunday
Mostly sunny, with a high near 55.
Click Map For Forecast
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Map Legend

ABOUT THIS FORECAST

 
Point Forecast:
Port Jefferson NY
 40.95°N 73.05°W (Elev. 151 ft)
Last Update:
10:31 am EDT Mar 17, 2025
Forecast Valid:
12pm EDT Mar 17, 2025-6pm EDT Mar 23, 2025
 
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