Abstract
The aim of this study is to assess the differences in the occurrence of harsh bioclimatic conditions between the center of Lublin and non-urban areas in the warm half of the year (April-September) and to determine the rate of changes in these conditions in both analysed meteorological stations in the years 1973–2022. To assess the bioclimatic conditions, the biometeorological index Humidex was used. In the first part of the study period, the number of days with unfavourable bioclimatic conditions prevailed in the city center, while in the last two decades the differences have decreased, mainly as a result of the development of concentrated buildings in the suburban area. In both measurement points, there was a significant increase in the number of days with strong thermal and hygric loads on the human body. The study also presents the reasons for the occurrence of selected cases with significant differences in the index values in the Lublin region, as well as the synoptic conditions on the day with the highest recorded Humidex value during the study period.