Current conditions at

Islip, Long Island Mac Arthur Airport (KISP)

Lat: 40.79°NLon: 73.1°WElev: 98ft.

A Few Clouds

77°F

25°C

Humidity 60%
Wind Speed N 7 mph
Barometer 30.11 in (1019.3 mb)
Dewpoint 62°F (17°C)
Visibility 10.00 mi
Heat Index79°F (26°C)
Last update 21 Jun 7:56 am EDT
Extended Forecast for

Port Jefferson NY

Extreme Heat Watch June 22, 12:00pm until June 24, 08:00pm
Click here for hazard details and duration
Extreme Heat Watch
  • Today

    Today: Sunny, with a high near 86. West wind 3 to 7 mph.

    High: 86 °F

    Sunny

  • Tonight

    Tonight: Partly cloudy, with a low around 70. South wind around 7 mph.

    Low: 70 °F

    Partly Cloudy

  • Sunday

    Sunday: A 20 percent chance of showers and thunderstorms before 2pm.  Mostly sunny, with a high near 91. Heat index values as high as 95. Southwest wind 10 to 14 mph.

    High: 91 °F

    Slight Chance
    T-storms

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 74. West wind 6 to 9 mph.

    Low: 74 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 93. Northwest wind around 7 mph.

    High: 93 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 72.

    Low: 72 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 94.

    High: 94 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 73.

    Low: 73 °F

    Partly Cloudy

  • Wednesday

    Wednesday: Mostly sunny, with a high near 87.

    High: 87 °F

    Mostly Sunny

Detailed Forecast

Today
Sunny, with a high near 86. West wind 3 to 7 mph.
Tonight
Partly cloudy, with a low around 70. South wind around 7 mph.
Sunday
A 20 percent chance of showers and thunderstorms before 2pm. Mostly sunny, with a high near 91. Heat index values as high as 95. Southwest wind 10 to 14 mph.
Sunday Night
Mostly clear, with a low around 74. West wind 6 to 9 mph.
Monday
Sunny, with a high near 93. Northwest wind around 7 mph.
Monday Night
Mostly clear, with a low around 72.
Tuesday
Sunny, with a high near 94.
Tuesday Night
Partly cloudy, with a low around 73.
Wednesday
Mostly sunny, with a high near 87.
Wednesday Night
Mostly cloudy, with a low around 66.
Thursday
Partly sunny, with a high near 80.
Thursday Night
A 30 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 66.
Friday
A 30 percent chance of showers and thunderstorms. Partly sunny, with a high near 79.
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ABOUT THIS FORECAST

 
Point Forecast:
Port Jefferson NY
 40.93°N 73.06°W (Elev. 161 ft)
3:17 am EDT Jun 21, 2025
8am EDT Jun 21, 2025-6pm EDT Jun 27, 2025
 
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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