Also, the whole “98.6 degrees” thing is a myth, human temperature varies. That 98.6 is an average from some old medical study. Just saying.
Slate explains the sweaty details:
“Because our bodies need to disperse heat, and they can’t do that effectively when the air temperature is close to our body temperature. Our muscles and metabolism generate heat continuously. We transfer that heat into our surroundings by sweating, exhaling warm air, and circulating blood near the surface of our skin to cool. When the temperature gradient (or difference) between the body and the air is high, heat flows easily from us into the environment, and we cool down. But when the weather hovers around our internal temperature, our inner swelter lingers, and we feel hot and uncomfortable. Humidity makes things worse by interfering with the vaporization of sweat, one of the human body’s main cooling mechanisms.”