Intense heat continues to bake a large portion of the U.S. this Tuesday, with portions of 17 states under heat advisories for dangerously high temperatures. The heat is particularly dangerous for the 1.4 million people still without power and air conditioning due to Friday’s incredible derecho event, which is now being blamed for 23 deaths. The ongoing heat wave is one of the most intense and widespread in U.S. history, according to wunderground’s weather historian, Christopher C. Burt. In his Sunday post, The Amazing June Heat Wave of 2012 Part 2: The Midwest and Southeast June 28-30, Mr. Burt documents that eighteen of the 298 locations (6%) that he follows closely because of their long period of record and representation of U.S. climate broke or tied their all-time heat records during the past week, and that “this is especially extraordinary since they have occurred in June rather than July or August when 95% of the previous all-time heat records have been set for this part of the country.” The only year with more all-time heat records than 2012 is 1936, when 61 cities of the 298 locations (20%) set all-time heat records. The summer of 1936 was the hottest summer in U.S. history, and July 1936 was the hottest month in U.S. history.