Forget #HeatIndex. #WetBulb Globe Temperature Is Where It’s At.

"One of the most common terms we hear during the summer when discussing the weather is Heat Index. While the Heat Index can give you an idea of how dangerous the heat can be, there is another lesser known variable that may give a complete description, known as the #WetBulbGlobeTemperature.

"The Heat Index is a measure of how hot it feels to the human body, taking into account the temperature and the relative humidity. The higher either one value is, the higher the heat index and the greater the stress exerted on the body. Heat Index utilizes the temperature measured in the shade and therefore will likely be greater in the sun, where many activities take place. For temperatures taken in the full sunlight, Heat Indices can increase as much as 15°F. Humidity plays a major effect on cooling the body. If the humidity is high, sweat on the surface of the skin does not evaporate as quickly, slowing the cooling of the body. If the humidity is low, sweat evaporates too fast, leading to dehydration. [See link for Heat Index chart]

"Wet Bulb Globe Temperature (#WBGT) is similar to the Heat Index in that it is an indicator of the stress on the body from the heat. While it is not as well-known as the Heat Index, it’s not a new term. WBGT was developed in the 1950s after heat related illnesses affected the US armed services during the 1940s. After its implementation, there was a reduction in heat related illnesses during basic training. One fundamental difference between the Heat Index and WBGT is that the latter is calculated with the temperature measured in the sun. While Heat Index only takes temperature and Relative Humidity into account, WBGT takes several variables into account.

These variables include:

- Temperature
- Humidity
- Wind Speed
- Sun Angle
- Cloud Cover
- Physical Activity"

Read more:
https://www.dtn.com/forget-heat-index-wet-bulb-globe-temperature-is-where-its-at/

#WetBulbTemperatures #GlobalWarming #HighHumidity #ExtremeHumidity #Heatwaves

#HeatIndex versus #WetBulb temperatures

The world needs a new way to talk about heat

by Michael J. Coren
July 25, 2023

"[The heat index] warning system is not perfect. First, it assumes you’re resting in the shade, not working in the sun. If you’re exerting yourself outdoors, the effective heat index could be 15 degrees higher. Secondly, the heat index was built on the idea of a young and healthy adult — a bad assumption for the elderly, very young and sick."

Read more:
https://www.washingtonpost.com/climate-environment/2023/07/25/heat-index-wet-bulb-temperatures-dangerous/

Archived version:
https://archive.ph/rwMSE

#ExtremeHeat #ExtremeHumidity #WetBulbTemperatures #ClimateChange #GlobalWarming

#WetBulb for #WashingtonDC on June 24, 2025 at 2:00pm EDT.

Forecast Maximum Temperature (F): 102°F (38.89°C)
DewPoint (F): 71°F
Relative Humidity (%): 37%
Wind Speed (mph): 5mph
Cloud Clover (%): 20%
Heat Index (F): 111°F (43.89°C)
Wet Bulb Temperature (F): 90°F

Source:
weather.gov/tsa/wbgt

#Heatwave #ExtremeHeat #ExtremeHumidity #ClimateChange #WetBulbTemp

#WetBulb Globe Temperature (Prototype-Under Development. Not to be used for operational use)

"The WetBulb Globe Temperature (WBGT) is a measure of the heat stress in direct sunlight, which takes into account: temperature, humidity, wind speed, sun angle and cloud cover (solar radiation). This differs from the heat index, which takes into consideration temperature and humidity and is calculated for shady areas. If you work or exercise in direct sunlight, this is a good element to monitor. Military agencies, OSHA and many nations use the WBGT as a guide to managing workload in direct sunlight."

https://www.weather.gov/tsa/wbgt

#ExtremeHeat #ExtremeHumidity #ClimateChange #WetBulbTemp

And if it's too hot for humans, it's probably too hot for other lifeforms.

How hot is too hot for humans? Understanding #Wetbulb temperatures

Humans sweat to keep cool. But when that sweat can't evaporate, heat gets dangerous

Jade Prévost-Manuel · CBC News · Posted: Jul 03, 2021

"At theoretical wet-bulb temperatures, evaporation and cooling can no longer take place because the atmosphere is fully saturated with water. And when the wet-bulb temperature reaches 35 C, it crosses a threshold at which humans can no longer lose internal body heat and cool themselves."

https://www.cbc.ca/news/science/how-hot-is-too-hot-for-humans-understanding-wet-bulb-temperatures-1.6088415

#Extinction #ExtremeHeat #ExtremeHumidity #ClimateCrisis