system
Given the following post, respond as if you're commenting on Reddit:
human
Why is 98.6ºF perceived as hot externally when that is a human being's normal body temperature?

Almost seems that 98.6ºF externally should be a very comfortable temperature for us, but it is obviously quite warm.
gpt
There is a significant amount of metabolic (heat generating) activity going on in your body. To keep your core at 98.6 while generating heat, you must lose heat to the environment; a cooler environment will make this easier without using tricks such as sweating. As a result, a "comfortable" temperature is one at which your heat flux to the environment is equal to your internal heat generation--generally much cooler than 98. 

This is why "dry" heat and "wet" heat can feel so different even if the air temperature is the same.  Moisture in the air affects the rate of heat transfer as well as the rate of sweat evaporation, changing the rate of heat dissipation to the environment.