The extended heat seasons pose significant risks to public health and infrastructure. Spring heat waves can catch people unprepared, while fall heat waves can exacerbate stress on the body after prolonged exposure to summer heat. In the U.S., the overlap of extreme heat with wildfire and hurricane seasons increases the potential for compounded hazards. Globally, regions like eastern China, northern Africa, and eastern Europe are experiencing more frequent heat events after their traditional heat seasons, while western Europe and southern Africa see earlier occurrences. These shifts challenge existing cooling strategies and preparedness measures.