When will the extreme heat end? What the current forecasts are saying

Keep the air conditioners running and the sunscreen handy -- the extreme heat in the U.S. is not going anywhere soon.

Portions of the country have been experiencing scorching temperatures over the past week, but significant relief from the stifling conditions will not come in the near future, forecasts show.

Heat waves are blanketing much of the country

Americans from coast to coast have been enduring dangerous heat waves over the last several days.

By Thursday, more than 60 million people in the West were under heat alerts, with some cities breaking all-time records for several days in a row.

Las Vegas saw five consecutive days of 115 degrees or higher, three of them surpassing 117 degrees, which had never been done before, records show. Other cities that experienced record highs were Phoenix, Tucson, Salt Lake City and Spokane, Washington.

When will the current heat waves end?

Persistent extreme heat is what's in store for the foreseeable future across much of the country, with no significant cool-down in sight, forecasts show.

The record-breaking heat in the West is going to expand and move into the Rocky Mountains, with record highs possible in Denver by Friday and Saturday.

While much of the region will experience brief relief from the dangerous heat between Thursday and Saturday, a new heat wave will begin to unfold on Sunday along the East Coast ushering in more dangerously hot conditions into the following week.

Cities from Boston to Washington, D.C., will experience temperatures in the 90s with heat indexes near or above 100 degrees.

That heat wave will last for most of next week, with record highs expected along the I-95 corridor.

July tends to be the hottest time in the year

Brutal summer heat will increase in frequency and duration for much of the country over the coming weeks.

The contiguous U.S. is now going into the hottest part of the year, which typically occurs during the month of July, records show.

The latest forecasts indicate that much of the country will likely see above-average temperatures for the remainder of July into early August. Several significant heat waves are likely for parts of the Northeast and West.

Much of the South typically experiences its peak average temperatures during the second half of August, while for some regions of the West Coast, the warmest temperatures of the year usually don't occur until September.

In the U.S., summer minimum nighttime temperatures are warming nearly twice as fast as summer maximum daytime temperatures, according to Climate Central.

Heat waves are becoming even more dangerous as overnight temperatures are too high to relieve people from the heat, prolonging heat stress and the associated heat risks, health experts say.

In June, approximately 24 million people across portions of the Northeast, South, and West experienced their warmest June overnight low temperatures on record, according to NOAA.

June 2024 was the warmest June on record and the thirteenth consecutive record-breaking month, according to the latest report by Copernicus, Europe’s climate change service, released earlier this week.

How extreme heat is connected to climate change

Human-amplified climate change is increasing the frequency and intensity of extreme heat events, according to climate scientists.

Heat waves are becoming more frequent, more intense and are lasting longer due to human-amplified climate change.

The average number of heat waves that major U.S. cities experience each year has doubled since the 1980s, according to the U.S. government’s Fifth National Climate Assessment.

ABC News' Matthew Glasser, Max Golembo, Daniel Manzo and Daniel Peck contributed to this report.