US and Canada Face Extreme Heat Dome as Temperatures Near 115°F

A broad heat dome over the eastern United States and southern Canada is driving temperatures into the high 90s and‑low 100s, with heat‑index values projected as high as 115 °F in parts of the Midwest and Northeast. The National Weather Service has placed millions of residents in Level 3 or Level 4 heat‑risk categories, warning that extreme heat kills more people in the U.S. each year than any other weather hazard.

Heat advisories and extreme‑heat watches have been issued from Ontario to Iowa, Illinois, Missouri and the Finger Lakes region. In Evansville, Indiana, city officials have opened library and rescue‑mission cooling centers for anyone needing air‑conditioned relief when temperatures exceed 90 °F. Southern and western states are also coping with dangerous fire weather; Utah received its first “particularly dangerous situation” red‑flag warning as the same high‑pressure ridge traps dry, windy conditions that threaten ongoing wildfires.

The pattern is expected to persist through the Fourth of July weekend, with only limited chances of isolated thunderstorms offering brief respite. Nighttime lows will remain in the 70‑80 °F range, providing little relief for those without reliable cooling. Health officials urge residents to stay hydrated, limit outdoor activity, check on vulnerable neighbors, and use available cooling centers.