Wet Bulb Globe Temperature
Also known as: WBGT
WBGT combines air temperature, humidity, wind and radiant heat into a single number. It's the most common index used to decide when it's too hot for people to work or exercise safely outside.
Scientific detail
Outdoor WBGT = 0.7 T_nwb + 0.2 T_g + 0.1 T_a, combining natural wet-bulb temperature (humidity), globe temperature (radiation) and dry-bulb temperature. WBGT thresholds are codified in ISO 7243 and used by militaries, athletic associations and OSHA to trigger work-rest and hydration protocols. Reflective canopies typically lower WBGT beneath them by 2–5 °C by cutting radiant load.
Related terms
Heat Stress
The thermal load a human body experiences from its environment.
Mean Radiant Temperature
The average temperature of every surface radiating heat toward a person.
Universal Thermal Climate Index
A modern, physiology-based heat index that estimates how the human body actually responds to weather.
Reflective Canopies
Overhead structures with a reflective upper surface that shade people and land beneath.
Where this concept shows up on MEER
Explore in topic hubs
Curated collections of MEER research, projects, publications and stories that feature this term.
Heat Resilience
MEER's work on heat resilience: physiological modeling with JOS-3, WBGT and UTCI measurement, HeatLens risk assessment, and community projects that protect the most exposed populations.
Urban Heat
The urban heat-island effect, its measurement, and how MEER's reflective roofs, canopies and pavements reduce peak city temperatures and protect vulnerable urban populations.
Measurement & Data
MEER's measurement stack: environmental sensors, physiological modeling (JOS-3), HeatLens risk assessment, and the data that grounds every deployment.