Heat index is based on humidity and wind, with wind I think playing less of a role.
I remember being in Albuquerque visiting relatives in high school and it was something like 104F out and did not even come close to feeling like it because it was so dry.
And this current heat wave with high humidity and temperatures in the 90’s is a killer.
Yeah, some of my favorite stories about heat were when I was a kid in Central Kansas. If the humidity was low and a good breeze was going, temps even up to 105 deg. F were not so bad to be in, so long as one had plenty to drink. If one (or vulnerable plants or whatever) didn’t, one “parched” rather quickly though...
In Kansas, we usually had a good breeze going.
Anyway, I did a search, and the heat index does not factor in direct sunlight (shade is assumed, of course), or cooling from wind. So, we are right about the latter.
NWS is now saying we will get a several day wet & warm period starting in a couple days. Hopefully cloud coverage will be intermittent, so everything does not mold or rust.