 It factors in how long it has been hot and where someone lives since a 90-degree day hits differently in Wisconsin than in Arizona. Dr. Narang has worked in the emergency department in Phoenix for 11 years. He says the tracker data reflects his own experience. I mean, there's no question the amount of heat-related illness and complaints are exponentially higher than when I first started here. That's because climate change is making heat waves longer and more intense. Alejandra Borunda, NPR News.