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

75°F

24°C

Humidity 90%
Wind Speed Calm
Barometer 30.06 in (1017.7 mb)
Dewpoint 72°F (22°C)
Visibility 10.00 mi
Last update 15 Jul 4:56 am EDT
Extended Forecast for

Islip, Long Island Mac Arthur Airport NY

  • Overnight

    Overnight: A 30 percent chance of showers and thunderstorms. Patchy fog. Otherwise, mostly cloudy, with a low around 74. Light southwest wind.

    Low: 74 °F

    Chance
    Showers and
    Patchy Fog

  • Tuesday

    Tuesday: A 30 percent chance of showers and thunderstorms, mainly before 11am. Patchy fog before 9am. Otherwise, cloudy through mid morning, then gradual clearing, with a high near 85. South wind 5 to 10 mph.

    High: 85 °F

    Chance
    Showers and
    Patchy Fog
    then Slight
    Chance
    T-storms

  • Tuesday Night

    Tuesday Night: Patchy fog after 11pm. Otherwise, partly cloudy, with a low around 74. South wind 5 to 8 mph becoming calm after midnight.

    Low: 74 °F

    Patchy Fog

  • Wednesday

    Wednesday: Patchy fog before 9am. Otherwise, mostly sunny, with a high near 88. Heat index values as high as 97. South wind 5 to 11 mph.

    High: 88 °F

    Patchy Fog
    then Mostly
    Sunny

  • Wednesday Night

    Wednesday Night: A 50 percent chance of showers and thunderstorms, mainly after 8pm. Mostly cloudy, with a low around 76. Southwest wind 8 to 10 mph.

    Low: 76 °F

    Chance
    T-storms

  • Thursday

    Thursday: A chance of showers, with thunderstorms also possible after 2pm. Partly sunny, with a high near 89. Chance of precipitation is 30%.

    High: 89 °F

    Chance
    Showers then
    Chance
    T-storms

  • Thursday Night

    Thursday Night: A chance of thunderstorms before 8pm. Partly cloudy, with a low around 78. Chance of precipitation is 30%.

    Low: 78 °F

    Chance
    T-storms then
    Partly Cloudy

  • Friday

    Friday: A 30 percent chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 90.

    High: 90 °F

    Mostly Sunny
    then Chance
    T-storms

  • Friday Night

    Friday Night: A 30 percent chance of showers and thunderstorms before 8pm. Mostly cloudy, with a low around 72.

    Low: 72 °F

    Chance
    T-storms then
    Partly Cloudy

Detailed Forecast

Overnight
A 30 percent chance of showers and thunderstorms. Patchy fog. Otherwise, mostly cloudy, with a low around 74. Light southwest wind.
Tuesday
A 30 percent chance of showers and thunderstorms, mainly before 11am. Patchy fog before 9am. Otherwise, cloudy through mid morning, then gradual clearing, with a high near 85. South wind 5 to 10 mph.
Tuesday Night
Patchy fog after 11pm. Otherwise, partly cloudy, with a low around 74. South wind 5 to 8 mph becoming calm after midnight.
Wednesday
Patchy fog before 9am. Otherwise, mostly sunny, with a high near 88. Heat index values as high as 97. South wind 5 to 11 mph.
Wednesday Night
A 50 percent chance of showers and thunderstorms, mainly after 8pm. Mostly cloudy, with a low around 76. Southwest wind 8 to 10 mph.
Thursday
A chance of showers, with thunderstorms also possible after 2pm. Partly sunny, with a high near 89. Chance of precipitation is 30%.
Thursday Night
A chance of thunderstorms before 8pm. Partly cloudy, with a low around 78. Chance of precipitation is 30%.
Friday
A 30 percent chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 90.
Friday Night
A 30 percent chance of showers and thunderstorms before 8pm. Mostly cloudy, with a low around 72.
Saturday
Mostly sunny, with a high near 85.
Saturday Night
Mostly cloudy, with a low around 72.
Sunday
A 40 percent chance of showers. Partly sunny, with a high near 86.
Sunday Night
A 30 percent chance of showers. Mostly cloudy, with a low around 73.
Monday
A 30 percent chance of showers. Partly sunny, with a high near 86.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Islip, Long Island Mac Arthur Airport NY
 40.81°N 73.11°W (Elev. 98 ft)
Last Update:
2:23 am EDT Jul 15, 2025
Forecast Valid:
5am EDT Jul 15, 2025-6pm EDT Jul 21, 2025
 
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