Summer swelter: Persistent heat wave breaks records, spirits

Mitchell Clearman takes a photo of a sign at El Arroyo restaurant in Austin, Texas, on a hot afternoon Thursday. (Jay Janner/Austin American-Statesman via AP)/

From the normally chilly Russian Arctic to the traditionally sweltering American South, big swaths of the Northern Hemisphere continued to sizzle with extreme heat as the start of summer more resembled the dog days of August.