The Wet Bulb Globe Temperature (WBGT) is a measure of heat stress in direct sunlight, and is not quite the same as heat index. which takes into account the following:
| WBGT | Heat Index | |
|---|---|---|
| Measured in the Sun | Y | N |
| Measured in the Shade | N | Y |
| Uses Temperature | Y | Y |
| Uses RH | Y | Y |
| Uses Wind | Y | N |
| Uses Cloud Cover | Y | N |
| Uses Sun Angle | Y | N |
Source: www.srh.noaa.gov/tsa/