Heat alerts cover more than 125 million Americans as record temperatures expected nationwide
Heat warnings and advisories are in effect for over 125 million people across the United States, with daily record highs forecast for several cities and smoke from Canadian wildfires expected to affect air quality.
More than 125 million Americans are under heat alerts stretching from Southern California to the Northeast, with extreme temperatures forecast for the coming days. Meteorological services expect daily record highs in Rapid City, South Dakota; Fargo and Grand Forks, North Dakota; and in Plattsburgh and Syracuse, New York. Several locations already tied or broke records on Monday, including Bismarck, North Dakota (105°F) and Rapid City (102°F).
The heat index could reach 100 °F or higher in many areas, prompting extreme heat warnings for places such as Fargo, Detroit, Philadelphia and Trenton, where indices may approach 105-107 °F. Southern California remains under heat alerts through Thursday, with interior valleys projected to hit 105-110 °F.
In addition to high temperatures, shifting winds are expected to carry smoke from more than 800 wildfires burning in Canada into the Upper Midwest and Northeast on Wednesday, raising air-quality concerns for millions of residents.
Separate weather threats include a level-3 flood risk in South-Central Texas, where rainfall could exceed 2 inches per hour and total three-day accumulations may surpass 15 inches in some locations. Northern New England faces a level-3 severe-storm risk on Tuesday, with the potential for wind gusts over 70 mph, large hail and isolated tornadoes as a cold front moves south.
Authorities advise residents in affected regions to monitor updates, stay hydrated, limit outdoor activity during peak heat, and follow local guidance regarding flood and severe-storm safety.