Parts of New Jersey remain under an excessive heat warning.
The National Weather Service says the warning remains in effect until 8 p.m. Wednesday for Mercer, Gloucester, Camden and northwestern Burlington counties.
Forecasters say temperatures and humidity will combine to make it feel like it's in the mid-90s.
Officials say that could pose a threat to the very old, the very young and pets that don't have access to air conditioning.
Officials advise people to drink plenty of fluids and don't leave anyone unattended in vehicles for any length of time.
In New York, temperatures will likely reach the high 80s; no official heat warning has been issued by the National Weather Service for the state.
There's a slight risk for thunderstorms which could break the heat throughout the tri-state later in the day, with temperatures Thursday and Friday expected to settle into a more comfortable, less humid range in the high 70s.
As always, check back with NBCNewYork.com for the latest weather information, including updated forecasts and severe weather alerts.