A major heat wave is set to lock in across the Midwest and East through the Fourth of July, bringing dangerous humidity, scorching afternoon highs and very warm nights. In some places, the heat could approach all-time records and leave little relief after sunset.
By late this week, more than 175 million people in the Midwest and East will face a risk of major or extreme heat-related health impacts, according to the National Weather Service’s experimental HeatRisk product. Triple-digit heat indices are expected in many areas, with overnight lows in some locations struggling to fall below the mid-80s.
Heat Alerts Spread Across The Eastern Half Of The Country
The National Weather Service has issued numerous extreme heat watches, warnings and advisories across the eastern half of the country this week. These alerts stretch from the Central Plains through the Midwest, South and Northeast.
An extreme heat watch means dangerous heat is possible, while a warning means it is happening now or is imminent. Heat advisories are issued for heat that is less unusual, but can still be dangerous.
| Region | Expected Conditions | Notable Risk |
|---|---|---|
| Northeast | Mid-90s to triple-digit highs in some areas | Possible record heat and very warm nights |
| Midwest | 90s are common, with heat indices reaching the triple digits | Dangerous exposure risk in major cities |
| South | Persistent 90s and some 100-degree readings | Heat indices well over 100 from Texas to the Carolinas |
Northeast Faces The Sharpest Spike
In much of the Northeast, the peak of the heat wave is expected from Wednesday through at least part of the holiday weekend. By Wednesday, highs in the mid-90s will be common from Virginia to parts of New England and upstate New York.
Parts of the I-95 corridor from southern New England to northern Virginia could reach triple-digit highs each afternoon from Thursday through Saturday. That could challenge all-time records in some cities, including Philadelphia, where the streak of 100-degree-plus highs and the all-time high of 106 degrees may both be threatened.
New York City’s Central Park could see its first triple-digit high in almost 14 years, while Harrisburg, Pennsylvania, could post its first back-to-back triple-digit highs in 15 years. Washington, D.C., may flirt with 100 degrees for three straight days, which could break a record for consecutive days above that threshold at Dulles International Airport.
Life-threatening heat indices will rise above 100 degrees in many areas and could top 110 degrees in the hottest parts of the mid-Atlantic states. Overnight lows may also struggle to drop below 80 degrees in Philadelphia, Baltimore, New York, Boston and Washington, D.C.
Midwest Heat Will Feel Even Worse Because Of The Humidity
The heat intensified in the Plains and Midwest over the past weekend and is now locking in across the Great Lakes and Ohio Valley for much of this week. In the Midwest, 90s will remain common, except in parts of the upper Midwest and Northern Plains where thunderstorms may provide some relief.
When heat index values are added in, many places will feel like the triple digits, including Milwaukee, Chicago, St. Louis and Minneapolis. The best chance for daily record highs will be in parts of the Ohio Valley and southern Great Lakes, including Cleveland and Detroit.
Detroit Metro Airport could flirt with a triple-digit high, which would be the first time that has happened there since July 17, 2012.
South Stays Hot, With Record Low Temperatures Already Falling
The South is used to hot summers, but the incoming heat will be both persistent and oppressive. Much of the region already saw highs in the 90s last weekend, and that torrid pattern is expected to continue through the week.
Some locations could top 100 degrees in the Southern Plains and in the Southeast from Virginia into the Carolinas, where daily record highs are most likely. With the humidity, heat indices are expected to climb well over 100 from Texas to the Carolinas.
Record lows have already been a major part of this heat event. Rockford, Illinois, dropped to 75 degrees on June 29, tying the daily record low from 1931, while Dallas fell to 81 degrees on June 29, matching the previous record set in 2024.
How Long The Heat May Last
The heat is expected to ease a bit over most of the Midwest by this weekend, with 90s possibly limited to areas near the Ohio Valley. Some relief should also reach parts of New England and the interior Northeast by Sunday.
More noticeable easing may arrive in the mid-Atlantic states by next Monday or Tuesday, as the heat dome responsible for the current pattern shifts westward. That would send much of the above-average heat back toward parts of the Plains and West.
For now, the holiday weekend remains at risk for dangerous heat across a broad stretch of the country, and the forecast will continue to be updated as the Fourth of July approaches.