Wet Bulb

Wet-Bulb Globe Temperature Monitoring

Provided by the Preventive Medicine Department

The Wet-Bulb Globe Temperature (WBGT) is a measure of the heat stress in direct sunlight, which takes into account: temperature, humidity, wind speed, sun angle and cloud cover (solar radiation). If you work or exercise in direct sunlight, this is a good element to monitor as a predictor of the potential impact on human performance. The military uses the WBGT as a guide to managing workload in direct sunlight. See the Work / Rest Times & Fluid Replacement Guide below for more information.

Latest Readings

WBGT Index: 69.52°F

as of 09/19/2018 03:14:59 PM

Heat Category: 0

Measurement Celsius Fahrenheit
Wet Bulb 15.4° 59.72°
Dry Bulb 30.6° 87.08°
Black Bulb 35° 95°
Humidity 8.5%

Work / Rest Times & Fluid Replacement Guide

Applies to average size, heat-acclimated Soldier wearing army combat uniform, hot weather (See TB MED 507 1 for further guidance)

Easy Work

  • Weapon Maintenance
  • Walking Hard Surface at 2.5 mph, < 30 lb Load
  • Marksmanship Training
  • Drill and Ceremony

Moderate Work

  • Walking Loose Sand at 2.5 mph, No Load
  • Walking Hard Surface at 3.5 mph, < 40 lb Load
  • Calisthenics
  • Patrolling
  • Individual Movement Techniques, i.e. Low Crawl, High Crawl, etc.

Hard Work

  • Walking Hard Surface at 3.5 mph, ≥ 40 lb Load
  • Walking Loose Sand at 2.5 mph with Load
  • Field Assaults
Heat Category WBGT Index, °F Easy Work Moderate Work Hard Work
Work/Rest Water Intake(Qt/H) Work/Rest Water Intake(Qt/H) Work/Rest Water Intake(Qt/H)
0 < 77.9° NL 1/2 NL 3/4 40/20 (60)* 3/4 (1)*
1 78.° - 81.9° NL 1/2 NL 3/4 40/20 (60)* 3/4 (1)*
2 (Green) 82.0° - 84.9° NL 1/2 50/10 (150)* 3/4 (1)* 30/30 (65)* 1 (1 1/4)*
3 (Yellow) 85.0° - 87.9° NL 3/4 40/20 (100)* 3/4 (1)* 30/30 (55)* 1 (1 1/4)*
4 (Red) 88.0° - 89.9° NL 3/4 30/30 (80)* 3/4 (1 1/4)* 20/40 (50)* 1 (1 1/4)*
5 (Black) > 90.0° 50/10 (180)* 1 20/40 (70)* 1 (1 1/4)* 10/50 (45)* 1 (1 1/2)*

The WBGT readings depicted on this website may differ from readings at other locations and will only be used as a guideline. Commanders must ensure WBGT monitoring devices are set up locally by the Field Sanitation Team to determine the WBGT index in the unit operating area.

Information for this table has been taken from the Heat Illness Fact sheet found on the Army Public Health Center Website.

Army Public Health Center: