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.

Overcast with Haze and Breezy

55°F

13°C

Humidity 77%
Wind Speed NW 22 G 33 mph
Barometer 29.61 in (1002.5 mb)
Dewpoint 48°F (9°C)
Visibility 6.00 mi
Wind Chill50°F (10°C)
Last update 12 Mar 8:56 am EDT
Extended Forecast for

Port Jefferson NY

  • Today

    Today: Rain before 3pm, then snow, possibly mixed with rain. Temperature falling to around 38 by 5pm. Breezy, with a northwest wind 15 to 22 mph. Chance of precipitation is 80%. Total daytime snow accumulation of less than a half inch possible.

    High: 53 °F⇓

    Breezy.
    Chance Rain
    then
    Rain/Snow

  • Tonight

    Tonight: Snow, possibly mixed with rain, becoming all snow after 7pm, then gradually ending. Low around 30. Northwest wind 8 to 10 mph. Chance of precipitation is 80%. New snow accumulation of less than a half inch possible.

    Low: 30 °F

    Rain/Snow
    then Mostly
    Clear

  • Friday

    Friday: Increasing clouds, with a high near 44. West wind 5 to 13 mph becoming south in the afternoon.

    High: 44 °F

    Increasing
    Clouds

  • Friday Night

    Friday Night: Mostly cloudy, then gradually becoming mostly clear, with a low around 36. South wind 10 to 13 mph, with gusts as high as 23 mph.

    Low: 36 °F

    Decreasing
    Clouds

  • Saturday

    Saturday: Mostly sunny, with a high near 48. West wind around 14 mph, with gusts as high as 25 mph.

    High: 48 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: Increasing clouds, with a low around 32.

    Low: 32 °F

    Increasing
    Clouds

  • Sunday

    Sunday: Cloudy, with a high near 47.

    High: 47 °F

    Cloudy

  • Sunday Night

    Sunday Night: Rain, mainly after 2am. Low around 40. Chance of precipitation is 80%.

    Low: 40 °F

    Chance Rain
    then Rain

  • Monday

    Monday: Rain. High near 56. Chance of precipitation is 90%.

    High: 56 °F

    Rain

Detailed Forecast

Today
Rain before 3pm, then snow, possibly mixed with rain. Temperature falling to around 38 by 5pm. Breezy, with a northwest wind 15 to 22 mph. Chance of precipitation is 80%. Total daytime snow accumulation of less than a half inch possible.
Tonight
Snow, possibly mixed with rain, becoming all snow after 7pm, then gradually ending. Low around 30. Northwest wind 8 to 10 mph. Chance of precipitation is 80%. New snow accumulation of less than a half inch possible.
Friday
Increasing clouds, with a high near 44. West wind 5 to 13 mph becoming south in the afternoon.
Friday Night
Mostly cloudy, then gradually becoming mostly clear, with a low around 36. South wind 10 to 13 mph, with gusts as high as 23 mph.
Saturday
Mostly sunny, with a high near 48. West wind around 14 mph, with gusts as high as 25 mph.
Saturday Night
Increasing clouds, with a low around 32.
Sunday
Cloudy, with a high near 47.
Sunday Night
Rain, mainly after 2am. Low around 40. Chance of precipitation is 80%.
Monday
Rain. High near 56. Chance of precipitation is 90%.
Monday Night
Rain likely, mainly before 2am. Mostly cloudy, with a low around 32. Chance of precipitation is 70%.
Tuesday
A 30 percent chance of rain. Mostly sunny, with a high near 40.
Tuesday Night
Partly cloudy, with a low around 25.
Wednesday
Mostly sunny, with a high near 37.
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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:
7:04 am EDT Mar 12, 2026
Forecast Valid:
9am EDT Mar 12, 2026-6pm EDT Mar 18, 2026
 
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Additional Resources

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Chance of Precipitation