Temperatures next week are expected to soar into the mid and low 90s, and the term “heat index” will be used in verbatim, but there is another way to determine how the heat will affect your body. That is through the “wet bulb globe temperature.”

The wet bulb globe temperature (WBGT) is the measure of heat stress on the body in direct sunlight. Now if you work in construction, the military, or any other outdoor profession you probably know what this is already — but for those who do not, this is typically a better measure on how heat will affect your body. For instance, the heat index is measured in the shade and only incorporates temperature and relative humidity while the WBGT uses temperature, relative humidity, wind, cloud cover, and sun angle to calculate a “temperature.”

For example, if we have a temperature of 92, relative humidity of around 46%, a wind of 5 mph, cloud cover of 10%, and a sun angle of 70 degrees we get a WBGT of 85. That number doesn’t seem too bad when the heat index with that could be close to 100. However, a WBGT of 85 degrees would require taking a 30 minute break for each hour of working or exercising in direct sunlight. A WBGT of this degree would begin to stress your body after 30 minutes as well.

There are various categories for the WBGT, but the higher that reading is the quicker heat will affect your body and the longer a break should be taken if not avoiding strenuous outdoor activities. If you’d like to learn more about the WBGT categories, head to this site!