Utility functions for calculating the Humidex.

Calculate Humidex from air temperature and the Dew Point.

The Humidex is a Canadian innovation first used in 1965. It combines the temperature and humidity into one number to reflect the perceived temperature. Because it takes into account the two most important factors that affect summer comfort, it can be a better measure of how stifling the air feels than either temperature or humidity alone. [1]

Air temperatures below 20c will give a generally meaningless result as the Humidex only describes perceived heat.

The Humidex is a “nominally dimensionless quantity” but is generally recognized by the public as equivalent to the degree Celsius [2]

Parameters
• ta – Air temperature [C]

• tdp – The Dew Point [C]

Returns

float – Humidex

Get the degree of comfort associated with a given Humidex value.

Degrees of comfort are provided by the Government of Canada and are indicated here with the following integer values:

• 0 = No discomfort (Humidex of 19 and below)

• 1 = Little discomfort (Humidex between 20 - 29)

• 2 = Some discomfort (Humidex between 30 - 39)

• 3 = Great discomfort; avoid exertion (Humidex between 40 - 45)

• 4 = Dangerous; heat stroke possible (Humidex of 45 and above)

Parameters

humidex – Humidex

Returns

int – Degree of Comfort