In addition to air temperature, humidity, air motion and the surface temperature of surroundings all have a significant influence on the rate at which the human body can dissipate heat. At temperatures below about 80°F (27°C) most of the body’s heat loss is by convection and radiation. Convection is affected mostly by air temperature, but it is also strongly influenced by air velocity. Radiation is primarily a function of the relative surface temperature of the body and its surroundings.