More than 125 million Americans are under the highest level of extreme heat alerts during a wave of above-average temperatures.

An "extremely dangerous heat wave" is continuing to scorch a huge area of the eastern United States June 23, affecting tens of millions of people.

"Dangerous heat will intensify across much of the Northeast and Mid-Atlantic early this week," meteorologist Jacob Hinson said.

The deadly heat wave across the eastern half of the country has made for some scary situations. Tens of millions in major cities across the northeast faced record high temperatures on Tuesday, the worst day of an oppressive heat wave that has spread since late last week.

Several cities in the eastern United States have faced record high temperatures due to a climate phenomenon known as the "heat dome."

Boston carpenter says the humidity is the worst as triple digit heat hits the East coast. (AP Video: Rodrique Ngowi)