Heck, 93 degrees with 90% humidity is a typical summer day here in the Florida Keys. That’s off the chart on your scale there. I have a construction company and I’ll tell you it’s absolutely brutal, but only twice in 25 years in business have i had to pack someone in ice from heat exhaustion, both times it was a newbie who did not know how to pace themselves or drink enough fluids.
Also it is often that their body is not acclimatized to the conditions. One should be watchful of folks returning from a vacation in air conditioning. You can lose your acclimatization in a matter of a few days in the A/C. Supervisors are also more subject to going down...standing still and not moving is deadly too.
At noon today, Key West is Temp 91, RH 53. Must not be a typical summer day.
http://www.srh.noaa.gov/key/HTML/obs.php