WBGT, or Wet Bulb Globe Temperature, is your body’s true heat stress scorecard. Unlike the heat index, which only considers temperature and humidity, calculating WBGT factors in the sun’s intensity, wind, and cloud cover. Think of it as a supercharged weather report designed to keep you safe. Whether you’re an athletic trainer or organizing an outdoor event, knowing how to calculate WBGT can be a game-changer for heat safety.

Calculating WBGT isn’t just for the weather geeks—it’s essential for anyone who spends time outdoors in the heat. Whether you’re using a WBGT calculator or crunching the numbers yourself, understanding this metric can help you dodge heat-related illnesses and keep your cool, no matter how hot it gets! This blog breaks down how to calculate WBGT and shows why calculating WBGT measurement is the key to keeping cool.

Outdoor WBGT Calculator

Our outdoor WBGT calculator helps you automatically measure the wet bulb globe temperature quickly and efficiently without any complicated input.

What is Wet Bulb Globe Temperature (WBGT)?

Wet bulb globe temperature (WBGT) is a measure of how the weather feels, specifically, heat stress in direct sunlight. It is a perceived or apparent temperature that combines multiple environmental factors such as air temperature, relative humidity, radiant heat, and air movement to assess heat stress conditions and provide a more accurate reflection of how the human body experiences heat.

Whether you’re using a WBGT calculator or performing manual calculations, understanding the components and methods to calculate WBGT is essential to manage heat exposure effectively.

Why Wet Bulb Globe Temperature (WBGT) Matters

Wet bulb globe temperature is an imperative guide for maintaining a proper workload in direct sunlight as well as deterring heat strokes during an excessive heat warning. This is especially important as it differs from the heat index, which only accounts for temperature and humidity in its calculation for shaded areas.

For instance, if the WBGT is below 80, no extra precautions are necessary. But if the wet bulb globe temperature is between 80-90, the body will stress within 20-45 minutes of work or exercise in direct sunlight, with the time until stress becoming shorter as the wet-bulb globe temperature increases. If the WBGT is above 90, the body will stress in just 15 minutes and it is crucial to drink plenty of fluids and take very frequent breaks in the shade.

Why Use WBGT to Calculate Heat Stress?

• It’s Apt for Outdoor Activity: Since WBGT is a measure of heat-related stress specifically, it is an important factor to consider anytime people are performing some kind of outdoor activity. To ensure the safety of working conditions, regulations are in place for WBGT monitoring, making it essential to calculate WBGT accurately.

• WBGT is Highly Valuable for High School and Collegiate Athletics: WBGT is also highly valuable information for high school and collegiate athletics, event venues, OSHA regulated construction, city sports leagues, and military training facilities. The applications are endless.
  For example, during a high school football practice, kids are training their hearts out in the heat of August. Knowing the wet bulb globe temperature can ensure that players in direct sunlight will not put a dangerous amount of stress on their bodies, as well as help the coaches know how often they can take breaks and need hydration.

• WBGT can even show you when humidity decreases: A humidity decrease generally causes a rise in temperature, which is perfect for snowmakers. Therefore, being able to calculate WBGT is also beneficial for winter sports and activities.

What is Wet Bulb Temperature?

When water evaporates into the air it creates a cooling effect, but the amount of this cooling varies depending on the overall air temperature and the relative humidity. Wet-bulb temperature measures how cool the air can become through water evaporation. It’s influenced by both temperature and humidity. Essentially, it reflects the body’s ability to cool itself through sweating. Here is the equation for wet bulb temperature:

This is a rather complex WBGT formula:

Tw = T * arctan[0.151977 * (rh% + 8.313659)^(1/2)] + arctan(T + rh%) – arctan(rh% – 1.676331) + 0.00391838 *(rh%)^(3/2) * arctan(0.023101 * rh%) – 4.686035

Here, “T” is the temperature in celsius, and “rh” represents the relative humidity.

With this final calculation, you can calculate WBGT completely.

Learn more about the differences between wet bulb temperature and wet bulb globe temperature here.

WBGT Calculators Ranked

Okay, that was a lot. But don’t panic!

You don’t really need a WBGT calculator or a formula to calculate the WBGT accurately. There are much faster and much, much easier ways to calculate wet bulb globe temperature.

The streamlined approach uses the latest technology to provide a multitude of industries with real-time updates to temperature, relative humidity, wet bulb temperature, globe thermometer temperature, and WBGT.

Using Perry Weather Weather Station software, you don’t need a manual WBGT calculator and it only takes the click of a button to receive consistently calculated wet bulb globe temperatures no matter where you are and ensure your people are safe in every job, every game, and every season.