We know that having a good heat stress plan for athletes greatly reduces the incidence of exertional heat illness (EHI) and death from heat stroke. One of the foundational elements of almost all heat stress plans is measuring the wet bulb globe temperature (WBGT) with a heat stress monitor. There are several heat stress meters that measure WBGT on the market. Which one should you use? The answer to that question is a big “it depends”. I will break down some different options for you depending on what your specific needs are.

Choosing the correct device is determined by a few different things. First thing is accuracy/precision. Does the use case require scientific levels of accuracy and precision? If so you are going to need to shell out a lot of cash and be trained in how to use the instruments. Or can you be within a degree or two for it to be acceptable (most use cases). Second, where are you using the device? Are you using it inside or outside? Are you using it in a location that blocks wind or causes heat trapping? One thing to note is the type of ground surface causes no significant change to the wet bulb globe temperature. Another question you need to ask is how much man power can I dedicate to obtaining a WBGT reading? If you use your own instrument, you have to spend at least 15 minutes everyday to obtaining an accurate WBGT vs the Zelus WBGT system that is instantaneous. Finally, how much money do you have available? Devices that give accurate WBGT readings can range from tens of thousands of dollars annually to free.

This list is my personal opinion and is not an exhaustive list of all devices. Each use case is unique and requires careful consideration when choosing a WBGT monitor. Also I make no claims about the accuracy of any of the listed devices.


Scientific or Meteorological Uses and Money Is No Object

Scientific black globe thermometer
black globe thermometer

If you are going to be doing something that requires the high precision and accuracy you are going to want to build your own device. You should purchase all three thermometers separately from a source like Campbell Scientific. Plan on spending well over $10,000 and also have the time and knowledge to maintain the equipment.

Scientific Field Work

You need something that is fairly accurate, portable, and won’t break the bank? The device to use would be the QUESTemp 34. The QUESTemp series has been proven to be the most accurate portable monitor on the market. It will set you back $3-4,000 and does require quite a bit of maintenance. But if you want accurate results for your research, this is the device you should look at.

Athletes That Play or Practice in Large Bowl Stadiums

Bowl Stadium
bowl stadium

Athletes that play in Stadiums that are enclosed on several sides will need to have on field measurements taken due to restricted air movement and possible heat trapping. There are several companies that offer this service such as WeatherSTEM and earth networks. These services are usually several thousand dollars annually. If that is out of your budget, a handheld device will work but it is prone to insolation error and user errors. The Extech ht30 has been proven to be the one of the more accurate handheld device and can be purchased for a few hundred dollars.

Athletes That Play Outside

soccer players
athletes playing in the heat

Disclaimer: seeing as how I invented this next option, I am very partial to it and biased. For most club, high school, middle school, and college athletics Zelus WBGT system is the best option. Zelus WBGT uses real time hyperlocal weather data and processes it through complex algorithms to give the user an accurate WBGT reading. But why is it the BEST option? Zelus WBGT system gives instant and accurate readings. It does not require any user maintenance. It is not affected by insolation error (hot car error). It is on your phone, so no more forgetting the device. Also the user can get the WBGT at any location, they are not required to be onsite. And it is FREE.

Outdoor Manual Labor Working in Artificially Hot Environments or Wind Restricted Environments

If you are concerned about workers outside on artificially hot surfaces such as road workers laying asphalt then I would recommend using the QUESTemp 46 or Extech ht30 depending on the available budget to get your WBGT readings. Anytime there is artificial heat added to the environment or the wind is restricted local readings are a must.

Outdoor Manual Labor

Grounds Keeper
grounds keeper working in the heat

For people who are working outdoors such as grounds keepers or farmers then I would recommend the Zelus WBGT system for obtaining the wet bulb globe temperature reading. The simplicity of use and ability to get instant readings, instead of waiting 15 minutes for the device to equilibrate, saves employers time and money.

Indoor Use

Occasionally you will need to have an indoor WBGT reading. Indoor WBGT readings are usually needed only in industrial settings. A large employer should either have someone on staff or hire a consultant to make the determination of what device is best for their particular use case. There are many different options and depending on what is required will determine the equipment needed to measure heat stress.


Depending on your use case, you can spend tens of thousands of dollars for a bespoke system that will measure heat stress and the wet bulb globe temperature all the way to the Zelus WBGT system that will provide you an accurate outdoor WBGT reading for free.

Until next time, stay cool! 😎

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