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

Islip, Long Island Mac Arthur Airport (KISP)

Lat: 40.79°NLon: 73.1°WElev: 98ft.

Light Rain Fog/Mist

53°F

12°C

Humidity 96%
Wind Speed S 8 mph
Barometer 29.77 in (1008.0 mb)
Dewpoint 52°F (11°C)
Visibility 4.00 mi
Wind Chill50°F (10°C)
Last update 5 Apr 3:56 pm EDT
Extended Forecast for

Port Jefferson NY

  • This Afternoon

    This Afternoon: Rain. Patchy fog. Steady temperature around 56. Southwest wind around 11 mph. Chance of precipitation is 100%. New precipitation amounts of less than a tenth of an inch possible.

    High: 56 °F

    Rain and
    Patchy Fog

  • Tonight

    Tonight: Showers likely before 8pm. Patchy fog before 9pm. Otherwise, cloudy during the early evening, then gradual clearing, with a low around 39. Northwest wind 8 to 10 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.

    Low: 39 °F

    Showers
    Likely and
    Patchy Fog
    then Mostly
    Clear

  • Monday

    Monday: Sunny, with a high near 53. West wind around 14 mph.

    High: 53 °F

    Sunny

  • Monday Night

    Monday Night: A 20 percent chance of showers. Partly cloudy, with a low around 38. West wind around 6 mph.

    Low: 38 °F

    Slight Chance
    Showers

  • Tuesday

    Tuesday: A 20 percent chance of showers before 2pm. Mostly sunny, with a high near 50. West wind 7 to 13 mph.

    High: 50 °F

    Slight Chance
    Showers

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 31.

    Low: 31 °F

    Mostly Clear

  • Wednesday

    Wednesday: Sunny, with a high near 47.

    High: 47 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 34.

    Low: 34 °F

    Mostly Clear

  • Thursday

    Thursday: Mostly sunny, with a high near 51.

    High: 51 °F

    Mostly Sunny

Detailed Forecast

This Afternoon
Rain. Patchy fog. Steady temperature around 56. Southwest wind around 11 mph. Chance of precipitation is 100%. New precipitation amounts of less than a tenth of an inch possible.
Tonight
Showers likely before 8pm. Patchy fog before 9pm. Otherwise, cloudy during the early evening, then gradual clearing, with a low around 39. Northwest wind 8 to 10 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.
Monday
Sunny, with a high near 53. West wind around 14 mph.
Monday Night
A 20 percent chance of showers. Partly cloudy, with a low around 38. West wind around 6 mph.
Tuesday
A 20 percent chance of showers before 2pm. Mostly sunny, with a high near 50. West wind 7 to 13 mph.
Tuesday Night
Mostly clear, with a low around 31.
Wednesday
Sunny, with a high near 47.
Wednesday Night
Mostly clear, with a low around 34.
Thursday
Mostly sunny, with a high near 51.
Thursday Night
Partly cloudy, with a low around 41.
Friday
Mostly sunny, with a high near 62.
Friday Night
Partly cloudy, with a low around 47.
Saturday
Mostly sunny, with a high near 66.
Saturday Night
Partly cloudy, with a low around 45.
Sunday
Mostly sunny, with a high near 60.
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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:
2:55 pm EDT Apr 5, 2026
Forecast Valid:
4pm EDT Apr 5, 2026-6pm EDT Apr 12, 2026
 
Forecast Discussion
 
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Additional Resources

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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