Humidex calculator for outdoor work
Enter the air temperature and relative humidity. The calculator works out the humidex the way Environment and Climate Change Canada does, and shows the comfort and heat stress level.
What the result means
- Below 30: little or no discomfort for most people.
- 30 to 39: some discomfort. Drink water often and take breaks in the shade.
- 40 to 45: great discomfort. Avoid heavy exertion, add rest breaks and watch for signs of heat illness.
- Above 45: dangerous. Heavy work should be rescheduled or tightly controlled.
- Above 54: heat stroke is likely. Stop heavy outdoor work.
Tell the crew
Run the heat stress toolbox talk and get it signed on the phone.
Sources
More help
What is an FLHA (Field Level Hazard Assessment)?GuideHow to complete an FLHA, step by stepGuideFree FLHA templateWord and PDFFLHA questions answeredSafety terms explainedHumidex calculator for outdoor workFree toolLadder setup calculatorFree toolWhat changed in 2026Rule changes with sourcesAll Canada guidesContact us