Sunday's heat broke records around the metropolitan area, including on Long Island, the National Weather Service said.
Islip hit a high of 90 degrees, a record for the date, with LaGuardia Airport hitting a record high of 94 degrees, the weather service said. Humidity, however, was relatively low, about 50%.
Monday will be slightly cooler, with a high of 85 degrees, and daytime peak temperatures will be in the mid- to high 80s until Thursday when conditions will cool. Lows at night will be in the mid- to high 60s, according to the forecast.
An air-quality alert was in effect through 11 p.m. Sunday for Nassau and Suffolk counties with elevated pollutant levels.
On Tuesday, there is chance of thunderstorms in the afternoon, increasing to 60% in the evening.
The temperature climbs to 87 on Wednesday with a 50% chance of thunderstorms through the night, when a low of 64 is forecast.
Thursday brings more sun and a high in the upper 70s and a nighttime low of 59.
Clouds bring cooler temps Friday. The high will top out at 73 before the temperature drops to 57 overnight, according to the weather service.