As the Northern Hemisphere experiences one of the most sweltering summers in recent decades, many people have their eyes glued to their weather apps, watching for any change in temperature. But aside from temperature there is another measurement these forecasts always provide: the heat index.
This little feature is wholly different from the simple temperature measurement one can see everywhere. Yet while the index has been around for nearly half a century, it has only recently become a major consideration for people around the world. But what, exactly, is it? And why is it so important? Click on to find out.