Wet-bulb globe temperature

Electronic WBGT meter
Analog WBGT meter consisting of three thermometers and a slide rule to compute WBGT

The wet-bulb globe temperature (WBGT) is a measure of environmental heat as it affects humans. Unlike a simple temperature measurement, WBGT accounts for all four major environmental heat factors: air temperature, humidity, radiant heat (from sunlight or sources such as furnaces), and air movement (wind or ventilation).[1] It is used by industrial hygienists, athletes, sporting events and the military to determine appropriate exposure levels to high temperatures.

A WBGT meter combines three sensors, a dry-bulb thermometer, a natural (static) wet-bulb thermometer, and a black globe thermometer.[2]

For outdoor environments, the meter uses all sensor data inputs, calculating WBGT as:

where

Indoors the following formula is used:

If a meter is not available, the WBGT can be calculated from current or historic weather data.[2] A clothing adjustment may be added to the WBGT to determine the "effective WBGT", WBGTeff.

  1. ^ "Prevention » Heat Hazard Recognition". Occupational Safety and Health Administration. Retrieved 10 September 2023.
  2. ^ a b "Section III, Chapter 4: Heat Hazard Assessment". OSHA Technical Manual. Occupational Safety and Health Administration. 15 September 2017.