The issue of the quantification of thermal comfort or heat stress on humans is on vogue nowadays. This is evident in the amount of indices or factors, which are trying to quantify these effects. Because of different aims of the development and the complexity of the issue close to 200 thermal indices have been developed and applied for different purposes, in different climate regions and for extreme climate conditions. Most of these indices rely on single meteorological parameters or a combination of them i.e. air temperature and air humidity. In the first half of the twentieth century the necessity of the inclusion of heat budget of the human body arised and in the second half of the twentieth century the first human energy balance models and complex thermal indices have been developed. The complex or rational thermal indices follow the concept of equivalent temperature, which is easier to be understood by users. Most known indices are PMV, PET, modified PET, SET* and UTCI. All the thermal indices require the same thermophysiological and meteorological parameters. For thermophysiology heat production and clothing are required. Air temperature, air humidity, wind speed, as well as short and long wave radiation fluxes in terms of the mean radiant temperature are the required meteorological parameters.
Especially the meteorological factors have to be available in an appropriate spatial and temporal scale depending on the target and the specific issues demanded. The appropriate spatial and temporal resolution data cannot be only delivered by measurement stations. Therefore the collection and availability of different data set is important and complex. Nowadays remote sensing, re-analysis, new techniques of interpolation and climate simulations data can also be used. Modelling issues in the context of human energy balance models and the derived thermal indices, as we as the generation and availability of meteorological data especially in complex topographies and urban areas is required. Meso and micro scale models, which compute not only the meteorological parameters and thermal indices, but also deliver relevant data and information for the climate conditions and can be helpful in the development of mitigation and adaptation strategies in the era of climate change. The main and secondary output can be helpful for different approaches in different disciplines and issues in the context of human health and welfare.
