Granted, but I still argue that the chart is subjective - temperature x at humidity y feels like temperature x'. My skepticism arises from the likely dearth of (surviving) people that know what an OAT of 180F feels like well enough to relate it to temp x at humidity y
I suspect they postulated a relationship that "worked" for a narrow range of conditions and then pushed the parametersay beyond any range where they should have had confidence in the results. Not an uncommon problem
Sure there is some subjective interpretation when you use the phrase "feels like," which I would probably have avoided had I been consulted on the implementation. Hah!
My points were to address the idea that heat index is some kind of deception or deliberate hoax being used to manipulate people for some reason I don't see. It's not. It's not a perfect tool, but it works really well for most people.
I also don't think most people use it in such a literal manner. I think they it helps them make the connection that that they're going to feel hotter in general when the humidity is higher and gives them a ballpark of when it's going to be dangerous (based on their own body and experienced) to be outside for prolonged periods. In that, it's a success.
I think it could be particularly useful for someone from a dry climate like Arizona or Colorado who is unaware of the additional stress high humidity puts on a body when the temperature is high. They may not have fully embraced that they can't rely on a wicking t-shirt and a breeze to keep them cool.
