01 What is the Humidex?


Humidex – an abbreviation for Humidity Index – refers to the perceived temperature based on the measured air temperature and relative humidity or dew point.

Humidex is a value used by Canadian metereologists to describe the influence of measured air temperature and humidity on the human body.

  • 20 to 29: Little to no discomfort
  • 30 to 39: Some discomfort
  • 40 to 45: Great discomfort; avoid exertion
  • Above 45: Dangerous; heat stroke quite possible

Humidex acquires its significance at air temperatures above about 20 to 25 °C. For air temperatures below about 10 °C, instead of humidity, wind speed is more important for the perceived temperature, which is expressed in the measure of Windchill.