Long Island Weather: Hour-By-Hour Climb To 103-Degree Heat Index

LONG ISLAND, NY — Somehow Monday will feel even hotter than Sunday on Long Island. A heat advisory remains in effect for the entire island, except for the South Fork, until 8 p.m.

Heat index values — what the temperature feels like to people as heat and humidity combine — up to 103 degrees are possible. The heat index will likely be in the triple digits throughout Monday afternoon, the National Weather Service.

At 8:56 a.m., it was 88 degrees at Republic Airport in Farmingdale. The heat index was already up to 98 degrees. See Monday's hour-by-hour forecast, which includes a slight chance of thunderstorms, below.

If you are heading to the beach, Jones Beach Field 6 was already filled to capacity at 9:35 a.m. See beach capacity updates. There is a moderate risk of rip currents at ocean beaches in Suffolk County.

The full forecast:

Monday- A 20 percent chance of showers and thunderstorms after noon. Mostly sunny, with a high near 96. Heat index values as high as 103. West wind 7 to 10 mph, with gusts as high as 20 mph.

Monday Night- A 20 percent chance of showers and thunderstorms before 9pm. Mostly clear, with a low around 73. West wind 5 to 7 mph becoming calm after midnight.

Tuesday- Sunny, with a high near 92. Northwest wind 5 to 7 mph becoming west in the afternoon.

Tuesday Night- A 20 percent chance of showers and thunderstorms after 9pm. Partly cloudy, with a low around 74. Light and variable wind.

Wednesday- A 50 percent chance of showers and thunderstorms. Partly sunny, with a high near 86. East wind 6 to 9 mph becoming southeast in the afternoon.

Wednesday Night- Showers and thunderstorms likely, mainly before midnight. Mostly cloudy, with a low around 74. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

Thursday- A 40 percent chance of showers and thunderstorms. Partly sunny, with a high near 89.

Thursday Night- A 30 percent chance of showers and thunderstorms. Partly cloudy, with a low around 71.

Friday- Sunny, with a high near 85.

Friday Night- Mostly clear, with a low around 70.