The US National Weather Service warned of a severe heat wave sweeping the Rocky Mountains and Northern Plains, affecting about 44 million people, with temperatures expected to exceed 38 degrees Celsius.

The agency noted that the peak of the heat wave will be today (Sunday), with temperatures expected to range between 38 and 43 degrees Celsius in several states, an increase of 8 to 13 degrees Celsius above seasonal averages.

It added that the heat wave will extend next week to the western and central regions of the United States, affecting millions of residents and hindering efforts to fight wildfires in the states of Colorado and Utah.

Southeastern states including Florida are also experiencing high temperatures, with the heat index in Miami expected to reach 43 degrees Celsius due to humidity.