The aim of the study is the assessment and analysis of the variability of human-bioclimatic conditions in southern part of Warsaw, depending on the atmospheric circulation in the long-term (1998–2015). The Universal Thermal Climate Index UTCI was applied to evaluate the human-bioclimatic conditions using meteorological data for the 12:00 UTC obtained from the WULS Ursynów weather station. In order to determine the relationship between the UTCI and its corresponding synoptic situation, the circulation type classification proposed by Lityński was used. It was found that the period from the second decade of April to the first decade of October is the most favourable one for recreation and relaxation. The situations not caused by thermal loads of humans are the most frequent and the values vary from 42.9% in October to 66.6% in August. Whereas weather conditions causing the ‘strong’ and ‘very strong heat stresses’ and the ‘strong’ and ‘very strong cold stresses’ were relatively rare. The analysis of influence of atmospheric circulation on bioclimatic conditions has shown that the most favourable conditions with no heat load (class 0) of the body occurred during cyclonic circulation in the summer (70%) mainly at advection from the North and South. Particular analysis of selected most strenuous days of the heat wave and the cold wave confirmed the occurrence of a high frequency of conditions stressing the human body with ‘strong’ and ‘very strong heat’ as well as ‘strong cold’ for most of the day during anticyclonic circulation in both cases.