Humidex

(short for humidity index) is a number which combines the air temperature in Celsius and the amount of humidity in order to give a single number to represent the perceived discomfort of weather that is hot and humid. It was devised by Canadian meteorologists and first used in 1965. The humidex is widely used in Canada and has been accepted in a number of other countries. Range of humidexDegree of comfortLess than 29No discomfort30 to 39Some discomfort40 to 45Great discomfort; avoid exertionAbove 45DangerousAbove 54Heat stroke imminent The humidex is calculated with the following formula:
Humidex = (air temperature) + h
where
h = (0.5555)*(e - 10.0);
e = 6.11 * exp(5417.7530 * ((1/273.16) - (1/dewpoint)))