How Important Is Humidity in Heat Stress?

Recent studies highlight the importance of humidity in accounting for extreme values of wet-bulb temperature, a proposed indicator of heat stress. But this result may be sensitive to the measure of heat stress used-an ongoing source of confusion. Plain Language Summary There is confusion about how to measure heat stress, in particular between the wet-bulb globe temperature often used to screen for dangerous heat at sporting events and in workplaces, the wet-bulb temperature beloved of weather geeks, and apparent temperature quoted to the public by weather services. Here these distinctions are demystified. The distinction between these quantities matters a lot when considering how important humidity is to heat stress.