What thermal comfort humans, animals and plants experience is related to more than temperature shown on a glass thermometer. Relative humidity levels in ambient air can induce more or less evaporative cooling. Measurement of the wet-bulb temperature normalizes this humidity effect. Mean radiant temperature also can affect thermal comfort. The wind chill factor makes the weather feel colder under windy conditions than calm conditions even though a glass thermometer shows the same temperature. Airflow increases the rate of heat transfer from or to the body, resulting in a larger change in body temperature for the same ambient temperature.