Using WebBulb Globe to Modify Activities

WetBulb Globe Temperature

The Mississippi High School Activities Association now mandates the use of wetbulb globe temperature readings for determining the safety of outdoor practices.  The sports medicine community has long recognized that the thermometer alone does not tell the story of heat safety, with factors like direct sunlight, humidity, wind, and air pressure playing a large role in how hot it “feels” compared to what the thermometer reads.  The single best method we have of measuring all of those factors is WetBulb globe temperature, a method of measurement that takes into account the other factors that can drive up the risk while being outside in the heat.  With the ready availability of free apps for smartphones that give temperatures in WBGT measures, this eliminates the need to purchase equipment specifically for making these readings, and added cost to schools difficult to prescribe during tough post-COVID financial times for some districts.

Ambient Temperature vs. Heat Index vs. WetBulb Globe Temperature

Thermometers measure simply temperature of the air that comes into contact with the sensor.  Heat index is slightly better, taking into account humidity and air temperature, but is calculated in a shady area.  The WBGT goes further measuring the effect of temperature, wind speed, humidity and the independent effect of direct sunlight to give a best overall estimate of how severe the heat stress is participants while doing outdoor activities.

Currently Available free Smartphone Apps:

  1. WeatherBug
  2. Zelus WBGT.
  3. Carrot Weather
  4. Weather FX
  5. Snowmax

How to use WBGT readings for practice

Many states have already implemented WBGT readings for practice and participation modifications.  Similar to temp and heat index readings previously prescribed, as WBGT readings rise, practice time and duration is shortened while rest and hydration breaks are increased.  Keep in mind, these regulations DO NOT remove the need to have a cold tub available for all outdoor practices, as some athletes will experience heat stress earlier due to size, physical fitness, or health conditions.

Helpful links:,activity%20modifications%20as%20WBGT%20rises.



Check Also

Sumrall wins 2024 MHSAA Class 4A Baseball Championship

1 2 3 4 5 6 7 R H E Ripley 0 0 0 0 …