OKLAHOMA CITY (KFOR) – With record-breaking heat combining with high humidity, school districts across Oklahoma are using a unique measurement to protect students practicing outside for their fall extra curricular activities.

The WetBulb Globe Temperature (WBGT) is a measure of the heat stress in direct sunlight.

According to the National Oceanic and Atmospheric Administration (NOAA), WBGT 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. WBGT allows for better guidance of direct sunlight conditions.

WBGTEffectsPrecautionary Actions
80-85Working or exercising in direct sunlight will stress your body after 45 minutes.Take at least 15 minutes of breaks each hour if working or exercising in direct sunlight
85-88Working or exercising in direct sunlight will stress your body after 30 minutes.Take at least 30 minutes of breaks each hour if working or exercising in direct sunlight
88-90Working or exercising in direct sunlight will stress your body after 20 minutes.Take at least 40 minutes of breaks each hour if working or exercising in direct sunlight
>90Working or exercising in direct sunlight will stress your body after 15 minutes.Take at least 45 minutes of breaks each hour if working or exercising in direct sunlight
Suggested Actions and Impact Prevention per NOAA

Many school districts are using WBGT to determine students’ safety during outdoor practice.

For example, Deer Creek Public Schools says outdoor activities, including practice and games or performances, will either be delayed or canceled when the WBGT reading is over 92.1 degrees.

Preparedness – What to do before doing outdoor activities when the WBGT is high:

  • Wear a hat and light weight, light fitting, light colored clothes.
  • Plan to take frequent breaks in shady areas.

Safety – What to do while doing outdoor activities when the WBGT is high:

  • Take breaks in the shade. Strenuous outdoor activities should be reduced, especially in direct sunlight where there is little ventilation.
  • Drink plenty of water or other non-alcohol fluids. Your body needs water to keep cool. Drink plenty of fluids even if you don’t feel thirsty.
  • Don’t get too much sun. Sunburn makes the job of heat dissipation that much more difficult

You can check the estimated WBGT near you on the National Weather Service website.