Apparent temperature

The measure is most commonly applied to the perceived outdoor temperature.

Apparent temperature was invented by Robert G. Steadman[3] who published a paper about it in 1984.

[4] It also applies, however, to indoor temperatures, especially saunas, and when houses and workplaces are not sufficiently heated or cooled.

Since there is no direct measurement of solar radiation in U.S. observation systems, and solar radiation can add up to 15 °F (8.3 °C) to the apparent temperature, commercial weather companies have attempted to develop their own proprietary apparent temperature systems, including The Weather Company's "FeelsLike" and AccuWeather's "RealFeel".

These systems, while their exact mechanisms are trade secrets, are believed to estimate the effect of solar radiation based on the available meteorological data that is reported (such as UV index and cloud cover).

A generalized view of the heat index showing how the perception of heat by the human body increases with temperature but more rapidly at higher humidity levels.