 Very hot in Houston, very hot elsewhere, too. ABC's Victor Okendo. Las Vegas could break a record today, a fifth consecutive day, over 115 degrees. Meteorologists at the National Weather Service offices said Las Vegas experienced the most extreme heat wave in the history of its record-keeping, which goes back to 1937. More than 161 million people around the U.S. were under heat alerts on Tuesday, especially out west. The heat now is suspect in the deaths of six people in Oregon.