Northeast Heat Warnings Issued Ahead of July Fourth Events

Multiday heat warnings were issued for New York, Boston and Philadelphia on Wednesday as hot, humid air moved into the Northeast just before Fourth of July weekend events. Temperatures in the high 90s Fahrenheit are forecast across the region, with Philadelphia and Boston possibly exceeding 100 degrees by Thursday. Humidity will push heat-index values higher, the National Weather Service said.

High temperatures combined with humidity increase risks of heat exhaustion and heat stroke, according to Dr. Alexander Azan of NYU Langone Health. People in northern cities have less acclimatization to extreme heat than residents of southern states, Azan said.

Concrete, asphalt and steel in cities retain heat and raise local temperatures, said Vijay Limaye, a climate scientist at the Natural Resources Defense Council. Officials in New York City said more than 200 teams of workers and volunteers will check on homeless residents and direct them to cooling centers.

City will open hundreds of cooling centers, including the Javits Center and outdoor misting stations. The American Kennel Club’s Museum of the Dog will allow visitors to bring dogs inside through Sunday. In Washington, D.C., where the temperature reached 95 degrees, children received cold water from U.S. Park Police while waiting in line for attractions on the National Mall.

Jeff Schlegelmilch of Columbia University Climate School said longer, hotter summers and higher humidity are consistent with observed climate trends.