Q. If our normal body temperature is about 98.6 degrees Fahrenheit, or 37 degrees Celsius, why aren’t we most comfortable when the temperature around us is the same?

A. It should be noted that the usual 98.6-degree normal reading is for core body temperature, not skin temperature, which is usually considerably lower, rising and falling with the ambient temperature.

It is at the skin surface that much of the excess heat from the body’s metabolism is discharged into the air, through radiation, conduction and convection and through evaporative cooling, which depends on sweating. Heat is carried to the skin surface by blood circulating through dilating blood vessels.

Heat flows from a warmer place to a cooler place, so if the temperature where skin meets air reaches a level at which the first three discharge systems cannot discharge enough heat, discomfort results. If the humidity is also elevated, interfering with evaporation, the discomfort is even worse.