Heat exposure · Measured sensor inputs
Understand WBGT inputs before interpreting heat exposure
Combine measured heat sensors without confusing WBGT with air temperature.
By HSECalc · Published
Check that this method fits your task
Unadjusted WBGT arithmetic from measured natural wet-bulb and globe temperatures, plus dry-bulb temperature for solar load. Not a weather-app heat index or a universal heat-work limit.
Choose your inputs and work through the steps
- Use appropriate measured sensors and record conditions, location and time. Select solar or no-solar mode for the assessment setting.
- Enter all temperatures in the selected unit. Changing the unit clears readings so a Celsius value cannot silently become Fahrenheit.
- Calculate the unadjusted WBGT. Use a competent heat assessment to interpret workload, clothing, acclimatisation and relevant guidance.
With solar load: 0.7 × natural wet-bulb + 0.2 × globe + 0.1 × dry-bulb. Without solar load: 0.7 × natural wet-bulb + 0.3 × globe.
A worked example
Illustrative values explain the tool; they are not prescribed inputs for your work.
- Fictional sensor readings: natural wet-bulb 25°C, globe 40°C, air 35°C.
- Solar mode: 0.7×25 + 0.2×40 + 0.1×35 = 29.0°C.
- Without solar load, those wet-bulb/globe inputs give 0.7×25 + 0.3×40 = 29.5°C. Select the appropriate mode, not the lower answer.
Read the result and decide what needs checking
A temperature result alone cannot assign a universally safe work/rest pattern. Keep conditions and measurement quality with the record.
The calculator is not an emergency triage tool. Use the site’s heat-illness response arrangements when a person is unwell.
Common questions
Can I enter ordinary wet-bulb from a weather app?
No. This tool requires natural wet-bulb sensor data.
Does one WBGT value set a safe work/rest cycle?
No. Workload, clothing, acclimatisation and the applicable assessment method matter.
What if conditions change during the day?
One reading is not a time-history assessment. Use representative monitoring and the appropriate heat-assessment method.
References and scope notes
Use the current official guidance and the instructions for your actual equipment. HSECalc is independent; a reference is not an endorsement. Read how we use methods and sources or report a correction.