As the Eastern US experiences a heat wave, officials are working to keep residents cool. However, measuring heat is not as straightforward as it seems. Researchers have developed various metrics to quantify heat, including the heat index, wet bulb temperature, and wet bulb globe temperature.

Heat Index

The heat index is a value calculated by combining air temperature and relative humidity to arrive at a ‘feels like’ air temperature. However, it has its limitations, as it assumes a healthy adult walking in the shade with the ability to keep their skin wetted with sweat.

According to David Romps, a climate scientist at UC Berkeley, the heat index can underestimate actual conditions by as much as 20 degrees Fahrenheit when both temperature and humidity are high.

Wet Bulb Temperature and Wet Bulb Globe Temperature

The wet bulb temperature measures how efficiently our bodies can cool down through sweating, while the wet bulb globe temperature incorporates factors like wind speed and solar radiation to assess heat stress. These metrics are more focused on the physiological effects of extreme heat on the human body.

Climate scientists tend to favor the use of the wet bulb temperature and wet bulb globe temperature in their studies of when and where heat stress may surpass the limits of human survivability.

Understanding the different heat metrics can be lifesaving, as heat is the number one weather-related killer in the US. Researchers emphasize the importance of communicating heat metrics effectively to convey the risks of heat stress.

Original reporting: KEYT (Ventura/Santa Barbara) — read the source article.