Definition of heat index according to the National Weather Service: “The Heat Index is a measure of how hot it really feels when relative humidity is factored in with the actual air temperature.” So when meteorologists talk about how it feels they are combining the two measures into one...At higher temps and humidities the body takes longer to cool, not to mention the fact that you can dehydrate faster. So the heat index helps people compare the conditions to temperatures in dry air to underline the dangers. The fact that some of the people posting are just dismissing it as people complaining are missing the point that heat waves can kill. I went through the 1995 heat wave in Chicago where about 740 people died because of the heat. It’s a serious issue.