Heat Stress (WBGT) Forecast
The WetBulb 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). This differs from the heat index, which takes into consideration temperature and humidity and is calculated for shady areas. If you work or exercise in direct sunlight, this is a good element to monitor. Military agencies, OSHA and many athletic departments use the WBGT as a guide to managing workload in direct sunlight.
Current WBGT: 39.9°F
Heat Risk: None
| Thursday | Friday | Saturday | Sunday | Monday | Tuesday | Wednesday |
|---|---|---|---|---|---|---|
| 56.9°F | 55.5°F | 64.3°F | 68.5°F | 71.4°F | 64.6°F | 65.3°F |
| No Risk | No Risk | No Risk | No Risk | No Risk | No Risk | No Risk |
Unacclimated and Acclimated Work/Rest and Water Intake Chart
| Heat Risk | Acclimated? | WBGT Index (°F) | Easy Work | Moderate Work | Hard Work | |||
|---|---|---|---|---|---|---|---|---|
| Work/Rest (min) | Water Intake (qt/hr) | Work/Rest (min) | Water Intake (qt/hr) | Work/Rest (min) | Water Intake (qt/hr) | |||
| No Risk | N | 78° – 81.9° | 50/10 min | 0.50 | 40/20 min | 0.75 | 30/30 min | 0.75 |
| Y | 78° – 81.9° | Continuous | 0.50 | Continuous | 0.75 | 50/10 min | 0.75 | |
| Low | N | 82° – 84.9° | 40/20 min | 0.50 | 30/30 min | 0.75 | 20/40 min | 1 |
| Y | 82° – 84.9° | Continuous | 0.50 | 50/10 min | 0.75 | 40/20 min | 1 | |
| Moderate | N | 85° – 87.9° | 30/30 min | 0.75 | 20/40 min | 0.75 | 10/50 min | 1 |
| Y | 85° – 87.9° | Continuous | 0.75 | 40/20 min | 0.75 | 30/30 min | 1 | |
| High | N | 88° – 90° | 20/40 min | 0.75 | 10/50 min | 0.75 | Avoid | 1 |
| Y | 88° – 90° | Continuous | 0.75 | 30/30 min | 0.75 | 20/40 min | 1 | |
| Extreme | N | > 90° | 10/50 min | 1 | Avoid | 1 | Avoid | 1 |
| Y | > 90° | 50/10 min | 1 | 20/40 min | 1 | 10/50 min | 1 | |
| Adapted from: 1) UGS Survey Manual, Management of Occupational Heat Stress, Chapter 45, Appendix A. 2)Manual of Naval Preventative Medicine, Chapter 3: Prevention of Heat and Cold Stress Injuries. 3) OSHA Technical Manual Section III: Chapter 4 Heat Stress. 4) National Weather Service Tulsa Forecast Office, Wet Bulb Globe Temperature. | ||||||||