Wet-bulb globe temperature
The wet-bulb globe temperature (WBGT) is a psychrometric measurement that reflects the sensation of heat felt by wet skin when it’s exposed to moving air. Because it measures the minimum temperature achieved by evaporative cooling, it allows temperature and humidity values to be examined in the context of the air currents inside a room.
In practice, this measurement is used to check that blown air from an air vent doesn’t create discomfort or cause occupants to become ill. This artificial air current reduces the WBGT and can therefore be unpleasant or even harmful if it’s too powerful. Consequently, this measurement is mainly relevant in the air conditioning season. The values below apply to an indoor setting with occupants engaged in low-level physical activity (not sweating):
||Minimum WBGT (°C)
||Maximum WBGT (°C)
The WBGT is a more meaningful metric for outdoor physical activity. People are advised to take precautions (taking regular breaks and drinking plenty of water) at values of 25°C or higher in direct sunlight. At readings below 21°C, the danger is considered negligible, whereas WBGT values in excess of 28°C poses a serious risk to health (heart attacks, etc.).