The toll from a stubborn heat wave gripping much of the United States climbed today, with at least 144 deaths linked to high temperatures and oppressive humidity stretching from Wichita to Boston.

While weather forecasters held out hope for some relief in the next day or two, big-city mayors, power company workers and hospital emergency room crews continued to fight the blistering effects of the 100-degree temperatures that have blanketed the south-central and eastern United States this week.

In Chicago, city officials said the heat may be responsible for more than 50 deaths. Chicago hit 104 degrees during the week, but a front moving through the region lowered temperatures to the 80s today.

Elsewhere, heat-related deaths continued to mount. One of the people who died in the Kansas City area was a 75-year-old man found dead in his home after he mistakenly turned on his heat instead of his air conditioning.

In New York, where temperatures had climbed above 90 for the last eight days, the thermometer reached a relatively refreshing 88 degrees in Central Park. So ended the hottest July in New York City history.

Chicago Mayor Richard M. Daley urged people to limit outside activities and check on elderly neighbors and relatives. Like many cities, Chicago kept several public cooling centers open. People in some areas of Chicago were encouraged to board air-conditioned city buses to escape the heat.

Ronna Campbell, visiting Chicago from Dallas this week, said the heat was extreme even by Texas standards. "Thursday and Friday was hot, hotter than Dallas," she said as she stood outside the Sears Tower in downtown Chicago.

In Boston, Mayor Thomas M. Menino declared a heat alert for the weekend, calling for extended hours at public swimming pools and air-conditioned community centers.

Although temperatures eased somewhat today, power companies continued to struggle with the extreme demand for electricity that resulted from this week's heat.

At least 26,000 people were without power in Chicago early this afternoon after two power substations went down Friday. A spokesman for Commonwealth Edison said the utility hoped to have power restored for most people tonight.

"We've broken seven peak demand records in the past two weeks," said Steve Solomon, spokesman for Commonwealth Edison.

The heat did offer some rewards, especially to those in the air conditioning business. Workers at appliance dealer Best Buy in Chicago said they had been sold out of window unit air conditioners for almost two weeks.

Some people were eager to unplug the air conditioning, including National Weather Service meteorologist Scott Reynolds, who said a cold front would bring cooler temperatures and perhaps even some rain to the East Coast on Sunday.

"Personally, I'm looking forward to turning off the air conditioning and opening all the windows at home," said Reynolds.

Parts of the East continued to sizzle, with temperatures in the eastern two-thirds of North Carolina soaring into triple digits today for a record-setting eighth time this year. Other temperatures were 108 in Hobart and Tipton, Okla.; 104 at Greenville-Spartanburg International Airport in South Carolina; 102 in Louisville and Parkersburg, W.Va.; 100 in Columbus, Ohio, and Columbus, Ind.; 99 in Philadelphia.

"It's like being in a sauna," said Jeni Humphries, who was selling groceries at a farmer's market in Montpelier, Vt. "Though in a sauna, you can just sit there, and in this you have to work."

Relief is in sight, according to Ken Reeves, senior meteorologist with AccuWeather in State College, Pa. "There is definitely a surge of more comfortable air coming in."