(CNN) -- When does 92 degrees feel cool? The day after 100.
Temperatures cooled a bit Thursday along parts of the East Coast that have been suffering under a blistering heat wave this week, but it might be too early to get out of the pool just yet. The National Weather Service still has heat advisories out for much of the region.
Even though in most places the mercury wasn't flirting with triple digits Thursday, the humidity was forecast to be stifling in places such as Philadelphia, Pennsylvania, and the District of Columbia. Because of that, the weather service warned that it might not feel any different outside there than it has in the past few days.
The heat shifted south Thursday and heat advisories went out for parts of Alabama, Mississippi, Tennessee and Kentucky.
Heat is the top weather-related killer, according to the National Oceanic and Atmospheric Administration. On average more than 1,500 people die in the United States each year from excessive heat, it says.
On Thursday, outdoor workers and firefighters took extra precautions.
Chuck Zurschmeide, a roofer in Louisville, Kentucky, started working at 3:30 in the morning to beat the heat, which was expected to reach 96 degrees there Thursday. Before 10 a.m., he was back in his truck for a blast of cool air. In his 28 years as a roofer, he said, this is the hottest he has seen.
"You got to understand, with that hot tar you're working with, it's probably about 150 degrees," said Zurschmeide, who was tackling a high school roofing project. "What's bad about the hot tar is you got to have gloves on and long-sleeved shirts on, Makes it even hotter."
He told his guys to take breaks on shady ground and put a cool rag on their heads.
"I won't let anybody die on a roof. It just ain't worth it," he said.
Five consecutive days of roasting temperatures have claimed at least two lives -- an elderly woman in Pennsylvania and a Maryland resident found inside a home with a temperature higher than 90 degrees.
And highs above the 100-degree mark were recorded Wednesday from New York City to Richmond, Virginia.
Air conditioners churned as crowds filled public pools and libraries, many of which were opened as cooling centers. Electrical companies pleaded with customers to conserve energy to help avoid massive outages.
Some people doused their pants with talcum powder. Others accepted their steamy fate, reminding themselves of chilling blizzards they were forced to endure just a few months back.
In New York, Lulis Leal -- who photographed people frolicking in the fountain at Washington Square Park for CNN's iReport -- said she was reminded of her childhood days spent without air conditioning in Mexico. She and her friends used to splash themselves in plaza fountains.
Another iReporter, Matt Sky, slipped "Ted the puppet" on his arm and ventured out in the heat to interview fellow New Yorkers about how they were coping. For him, it was a way to keep busy and stay distracted.
"Without air conditioning myself, it was the choice between sitting inside and roasting away or going out and seeing how others are dealing with the temps," he said. "It was ridiculous yesterday."
By his video's end, Ted wound up inside a grocery store's frozen vegetables section. Sky was wishing he could join his puppet.
In the District of Columbia, the fire and emergency office was taking up to 700 calls a day, a spike from the usual 450, said spokesman Pete Piringer.
He said extra precautions were being taken to ensure the safety of firefighters, sending them to medics to have their vital signs checked or making them sit in cooling chairs. The time they were allowed to be directly engaged in fighting a fire was cut in half, Piringer said.
"The most important thing you can do is slow down a bit and hydrate," he said.
On the other side of the country, Oregon and Washington braced for another sizzling day.
Portland, Oregon, set record highs Wednesday and had a chance to do it again Thursday as a high of 99 was forecast. The record for the day is 98 degrees, set in 1952, according to meteorologist Nick Allard of CNN affiliate KGW-TV.
Some Portland residents found shady spots for outdoor lunches. Others headed straight to fountains.
Employees at a Portland drug store reported furious sales of fans and air conditioners, slow sellers so far this year. Susan Simpson, manager at Hollywood Rite Aid, told KGW that she expected her shelves to quickly empty of the remaining stock of fans.
"People in Oregon aren't used to that hot of weather, so they need to get something to help them through it," she said.
The extreme heat caused scattered power outages in some states.
In the New York area, Con Edison restored electrical service to about 42,800 customers affected by the heat and urged its customers to continue to conserve. About 1,800 people remained without power Thursday morning and the company said it was distributing dry ice to those customers.
CNN's Chad Myers, Mackenzie Green, Jessica Naziri, Jason Kessler, Mythili Rao, Cassie Spodak, and Ashley Vaughn contributed to this report.