National Weather Service Forecast for: Islip NY
Issued by: National Weather Service New York, NY
Updated: 7:08 am EDT Jun 30, 2026
 
Today

Today: Mostly sunny, with a high near 83. South wind 9 to 15 mph.
Mostly Sunny

 Tonight

Tonight: A 20 percent chance of showers and thunderstorms after 11pm. Partly cloudy, with a low around 70. Southwest wind 10 to 15 mph, with gusts as high as 26 mph.
Slight Chance
T-storms

 Wednesday

Wednesday: A 20 percent chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 85. Southwest wind 10 to 15 mph.
Mostly Sunny
then Slight
Chance
T-storms
 Wednesday
Night
Wednesday Night: A 20 percent chance of showers and thunderstorms. Partly cloudy, with a low around 72. Southwest wind 9 to 13 mph, with gusts as high as 23 mph.
Slight Chance
T-storms

 Thursday

Thursday: Sunny, with a high near 94. Southwest wind 8 to 13 mph.
Sunny

 Thursday
Night
Thursday Night: Mostly clear, with a low around 77.
Mostly Clear

 Friday

Friday: Sunny, with a high near 96.
Sunny

 Friday
Night
Friday Night: Partly cloudy, with a low around 76.
Partly Cloudy

 Independence
Day
Independence Day: A 30 percent chance of showers after 2pm. Mostly sunny, with a high near 91.
Mostly Sunny
then Chance
Showers
Hi 83 °F Lo 70 °F Hi 85 °F Lo 72 °F Hi 94 °F Lo 77 °F Hi 96 °F Lo 76 °F Hi 91 °F

Hazardous Weather Outlook
Extreme Heat Watch
 

Today
 
 Mostly sunny, with a high near 83. South wind 9 to 15 mph.
Tonight
 
 A 20 percent chance of showers and thunderstorms after 11pm. Partly cloudy, with a low around 70. Southwest wind 10 to 15 mph, with gusts as high as 26 mph.
Wednesday
 
 A 20 percent chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 85. Southwest wind 10 to 15 mph.
Wednesday Night
 
 A 20 percent chance of showers and thunderstorms. Partly cloudy, with a low around 72. Southwest wind 9 to 13 mph, with gusts as high as 23 mph.
Thursday
 
 Sunny, with a high near 94. Southwest wind 8 to 13 mph.
Thursday Night
 
 Mostly clear, with a low around 77.
Friday
 
 Sunny, with a high near 96.
Friday Night
 
 Partly cloudy, with a low around 76.
Independence Day
 
 A 30 percent chance of showers after 2pm. Mostly sunny, with a high near 91.
Saturday Night
 
 A 40 percent chance of showers before 2am. Mostly cloudy, with a low around 73.
Sunday
 
 A 30 percent chance of showers. Mostly sunny, with a high near 89.
Sunday Night
 
 A 30 percent chance of showers. Mostly cloudy, with a low around 71.
Monday
 
 A 30 percent chance of showers. Partly sunny, with a high near 84.

 

Forecast from NOAA-NWS for Islip NY.