Utility function for calculating Discomfort Index (DI).

Calculate discomfort index (DI) from air temperature and relative humidity.

Discomfort Index is derived from original work carried out by Eral C. Thom [1] which defined discomfort index based on dry-bulb and wet-bulb temperature. It is the human-perceived increase in air temperature due to humidity increase.

Note

[1] Thom, E.C. (1959) “The Discomfort Index”. Weatherwise, 12, 57-61.

Parameters
• ta – Air temperature [C]

• rh – Relative humidity [%]

Returns

di – Discomfort index [C]

Get the category of effect associated with a given discomfort index (DI).

Each number (from -6 to 3) represents a certain DI thermal sensation category. With categories being the following:

• -6 = Hyper-glacial

• -5 = Glacial

• -4 = Extremely cold

• -3 = Very cold

• -2 = Cold

• -1 = Cool

• 0 = Comfortable

• 1 = Hot

• 2 = Very hot

• 3 = Torrid

Parameters

di – Discomfort Index [C]

Returns

category – An integer indicating the level of effect associated with the discomfort index. Values are one of the following:

• -6 = Hyper-glacial

• -5 = Glacial

• -4 = Extremely cold

• -3 = Very cold

• -2 = Cold

• -1 = Cool

• 0 = Comfortable

• 1 = Hot

• 2 = Very hot

• 3 = Torrid