Daily highs in the upper-90s to near 100 degrees are forecast to combine with humidity to create conditions where the “feels like” temperatures could exceed 110-115 degrees, according to a July 25 forecast by Jennifer Tate at the prediction center.
A dome of high pressure sitting over the eastern part of the country will help trap the heat while abundant moisture in the air will make actual temperatures feel several degrees warmer. The unusual heat and humidity could linger for several days, keeping heat risk in the major to extreme categories through the end of the month across much of the eastern United States.
The dangerous heat will be longest lasting across the Tennessee Valley/mid-South region and the Southeast into the Carolinas, said a Friday forecast by Jennifer Tate at the Weather Prediction Center. Morning lows in the 70s "will not provide much relief." Farther north, into the Midwest, Ohio Valley and mid-Atlantic can expect hotter-than-normal temperatures into the 90s.
Forecast maps from the weather service show the United States blanketed in warm shades of purple, red and orange, signifying intense heat. By July 30 or 31, a cold front is expected to help cool things in the Ohio valley region.
Anyone who absolutely must be outside should take extra precautions to stay hydrated and keep their body safe, according to the American Red Cross.
The heat isn't the only danger presented by the high pressure area dominating conditions. Interactions in the atmosphere around the perimeter of the heat dome are forecast to trigger thunderstorms and heavy rain.
"We've always had heat waves," said Max Holmes, president and CEO of the Woodwell Climate Research Center in Woods Hole, Massachusetts. "But it's happening a lot more, with greater intensity, greater duration and greater frequency."
"This is exactly what we expected to happen," Holmes said. "As the earth gets warmer, we see more extremes and it's the extremes that get us. They kill us. They make us sick."
Heat may be the most obvious, but there are others, including drought and the extreme rainfall that caused the deadly flash flooding in Texas Hill Country on July 4, he said. These extremes can be seen in the current heat wave, with forecasts for record breaking temperatures under the high pressure area, and intense rainfall in storms around the perimeter of the heat dome.
June 2025 was the seventh hottest June on record, according to data from the National Oceanic and Atmospheric Administration.
During the first two weeks of July 2025, temperatures across the country were an average of 1.5 degrees warmer than the most recent 30-year normal. Historical data from the weather service shows average temperatures in July have trended roughly 2.7 degrees warmer since 1950.
If a human body temperature is normally 98.6 degrees and warmed 2.7 degrees, it would be the equivalent of having a fever of 101.3. In nature, such an increase has a similar effect, scientists explain.
Average overnight temperatures across the country have climbed even higher than daytime high temperatures, the weather service data shows. That means the landscape, trees and buildings don’t get a chance to cool down, so they can heat up even faster the next day.
Extreme levels of heat stress have more than doubled over the past 40 years, according to NASA, and that trend is forecast to continue.
An analysis by Climate Central, published July 21, concluded human-caused climate change made the recent excessive heat at least three times more likely for nearly half the population of the United States.
“This is not your grandmother’s heat wave," said Kristina Dahl, Climate Central's vice president of science. "Yes, July is usually a hot month, but climate change is making this heat wave significantly hotter — and therefore more dangerous — than heat waves of the past.”
