More than 82 million Americans from California to New Hampshire are on alert for extreme heat Friday as the nation's deadly, unwavering heat wave pushes on.
In the Northeast, heat advisories have been issued from Delaware to New Hampshire -- and the heat is expected to intensify this weekend.
MORE: How to look out for neighbors during an extreme heat waveRecord-high temperatures are forecast for Sunday from Philadelphia to New York City to Boston.
New York City's Triathlon and Duathlon is shortening the run and bike portions of Sunday's race due to the dangerous heat.
MORE: Record-breaking heat waves in US and Europe prove climate change is already here, experts sayPhiladelphia has enacted a heat health emergency.
In Boston, a heat emergency has been extended through Sunday. The city said cooling centers will be open and more than 50 splash pads are available.
The Boston Triathlon, set for this Sunday, has been pushed back a month due to the heat, race organizers said.
MORE: Extreme heat safety tips: What to know about heat stroke vs. heat exhaustionThe heat wave is also persisting in the South and the West.
Hard-hit Texas reached record highs in Austin (105 degrees) and San Antonio (102 degrees) on Thursday.
MORE: Hot car safety tipsDallas County reported its first heat-related death of the year on Thursday. The county's Department of Health and Human Services said the victim was a 66-year-old Dallas woman with underlying health conditions.
Record highs are possible on Friday in Memphis, where the record stands at 103 degrees, and Phoenix, where the record is 116 degrees.
Click here for tips to keep yourself safe in the heat.