The purpose of the work is to evaluate the variability of bioclimatic conditions and their diversity in areas of a different degree of anthropogenic transformation. An important element of the work is to determine frequency of certain biothermal conditions in the analysed areas, strongly exposing the human body to heat and causing thermal stress of a various intensity. The most important meteorological parameter considered in this paper was the air temperature, because out of physical stimuli it is the one which is most intensely perceived, especially when its fluctuations occur at short-time intervals. The research was based on the meteorological data made available by the Voivodship Inspectorate of Environmental Protection (WIOŚ). The data come from automated measurement stations operating as part of air quality monitoring system, located in different districts of Warsaw and outside the city. Each of the stations is marked by individual features resulting from a different degree of anthropogenic transformation of the closest surroundings.