 People are most likely to feel a draft on uncovered body parts such as their head, neck, shoulders, ankles, feet, and legs, but the sensation also depends on the air speed, air temperature, activity, and clothing.Thermal stratification that results in the air temperature at the head level being higher than at the ankle level may cause thermal discomfort.ASHRAE Standard 55 recommends that the difference not be greater than 3 °C (5.4 °F) for seated occupants or for standing occupants 4 °C (7.2 °F).