Map of land surface temperature anomalies for June 17–24, 2012. The map depicts temperatures compared to the 2000–2011 average for the same eight-day period in June. (Land surface temperatures (LST) are distinct from the hot air temperatures that meteorological stations typically measure.)
The Summer 2012 North American heat wave was one of the most severe heat waves in modern North American history. It resulted in more than 82 heat-related deaths across the United States and Canada,[2][3] and an additional twenty-two people died in the resultant June 2012 North American derecho. This long-lived, straight-line wind and its thunderstorms cut electrical power to 3.7 million customers.[4] Over 500,000 were still without power on July 6, as the heat wave continued.[5] Temperatures generally decreased somewhat the week of July 9 in the east,[6] but the high pressure shifted to the west, causing the core of the hot weather to build in the Mountain States and the Southwestern United States shifting eastwards again by mid-July. By early August, the core of the heat remained over the Southern Plains.[7][8]