The medical examiner's office said Wednesday that the hyperthermia deaths included three in the Bronx, four in Manhattan and one in Queens. They ranged in age from 48 to 97.
Spokeswoman Ellen Borakove said toxicology tests can delay certification of heat-related deaths.
All of the individuals died between July 22 and July 25 except a 64-year-old woman from the Bronx. She died on Aug. 21.
Borakove said the Bronx woman had been hospitalized since dangerous heat and humidity scorched the city with temperatures in the 90s and 100s in July.