Wet Bulb Global Temperature Information Project

Why is the 35°C threshold being revised Health studies show lower limits : Experiments with healthy young adults have found that severe heat stress can occur at wet-bulb temperatures as low as 31.5°C. Experimental findings : In controlled experiments, critical wet-bulb temperatures for healthy young adults ranged from 25°C to 28°C in hot-dry environments and 30°Cto 31 °C in warm-humid environments. Lower limits for vulnerable groups : Research suggests that older adults have even lower survival limits, ranging from 21.9°C to 27.8°C Uncompensable heat stress : The point at which the body can no longer cool itself through sweating is reached at a lower wet-bulb temperature than the theoretical 35°C. Real-world events : Recent heatwaves have seen wet-bulb temperatures in the 31°C to 33.6°C range, demonstrating that these lower thresholds are being reached in the real world. Britain is surprisingly humid. Anyone who suspects that the above Wet Bulb Global Temperature Chart is o...

  What are Wet Bulb Temperatures? Wet bulb temperature  measures the combined effect of heat and humidity, representing the lowest temperature achievable by evaporating water into the air .  It is measured using a thermometer with a water-soaked cloth over its bulb, and it always reads lower than or equal to the dry bulb temperature. A higher wet bulb temperature indicates higher humidity, which hinders evaporation and reduces the body's ability to cool itself through sweating. This makes it a critical metric for assessing heat stress on humans and is often higher than the commonly reported heat index. Why Wet Bulb Temperatures are important Humidity and Evaporation :  The wet bulb temperature is essentially a measure of how well water can evaporate into the air. Human Cooling : Our bodies cool through the evaporation of sweat. High wet bulb temperatures mean less evaporation, making it harder to cool down and leading to dangerous heat stress.   H...