Video: What does the term 'humidex' actually mean? The sun shines on people standing on the roof observation deck of the Griffith Observatory, as a potentially dangerous heat wave grips the western U.S., in Los Angeles, California, June 29, 2013. Dozens of people were treated for heat-related ailments, and cities and towns across the western United States took emergency measures to help residents cool off, as the region sweltered on Saturday in dangerous triple-digit temperatures. Published Friday, Jul. 19, 2013 11:07AM EDT Last updated Friday, Jul. 19, 2013 11:08AM EDT