The Method of the Deutscher Wetterdienst for the Assessment of Cold Stress and Heat Load for the Human Body

In the past, numerous simple thermal indices have been developed in order to describe the complex conditions of heat exchange between the human body and its thermal environment. For cold conditions the approaches consider combinations of temperature and wind velocity, focusing on the turbulent flux of sensible heat with the windchill equivalent temperature as the best example. Heat load conditions have been mainly described by combinations of temperature and one measure of humidity to express the role of latent heat flux. However, none of these old and still partly popular indices take into account all mechanisms of heat exchange. Thus they are not universally valid and cannot be applied to all climates, all regions, every season and every scale. Only complete heat budget models are sufficiently powerful to assess the thermal environment in thermophysiologically significant way.