Wet-bulb globe temperature


The wet-bulb globe temperature is a type of apparent temperature used to estimate the effect of temperature, humidity, wind speed, and visible and infrared radiation on humans. It is used by industrial hygienists, athletes, sporting events and the military to determine appropriate exposure levels to high temperatures. It is derived from the following formula:
where
Indoors, or when solar radiation is negligible, the following formula is often used:

Uses

The American Conference of Governmental Industrial Hygienists publishes threshold limit values that have been adopted by many governments for use in the workplace. The process for determining the WBGT is also described in ISO 7243, Hot Environments - Estimation of the Heat Stress on Working Man, Based on the WBGT Index. The American College of Sports Medicine bases its guidelines on the intensity of sport practices based on WBGT.
In hot areas, some US military installations display a flag to indicate the heat category based on the WBGT. The military publishes guidelines for water intake and physical activity level for acclimated and unacclimated individuals in different uniforms based on the heat category. The University of Georgia adapted these categories for use in college sports as a guideline for how strenuous practices can be. Athletic organizations, industrial plants, and even the military rely on live WBGT readings for industry compliance. Utilizing an on-site weather station with a WBGT sensor such as, , is vital for monitoring heat stress.

Related temperature comfort measures

The heat index used by the U.S. National Weather Service and the humidex used by the Meteorological Service of Canada, along with the wind chill used in both countries, are also measures of perceived heat or cold, but they do not account for the effects of radiation.
The "WBGT" temperature readings are offered by , a commercial weather forecasting company, since American weather observation systems do not measure solar radiation directly).