A dangerous heat wave is sweeping across the United States, impacting over half the country. The heat poses a significant risk to public health and threatens to disrupt Fourth of July celebrations, a major holiday travel period. Record-breaking temperatures are anticipated from the Midwest to the East Coast. Authorities are urging residents to take precautions against heat-related illnesses, including staying hydrated and limiting outdoor activities. The extreme heat conditions could strain energy grids due to increased air conditioning usage. This widespread heat event is prompting concerns for vulnerable populations and potential disruptions to holiday travel plans.