Introduction: Traditional architecture, all over the world, has many characteristics that ensure thermal comfort. In the past, people built their houses in harmony with the environment, while also optimally utilizing the building materials available locally. The traditional built form was climate-responsive; it evolved over centuries of experience and observations of climate and nature. The traditional local architecture of Lucknow (a North Indian historical city) has employed some ingenious natural and passive techniques to maintain thermal comfort within the building, particularly during the hottest hours of the day. In this paper, we discuss the traditional built form of Lucknow through the lens of its climatic appropriateness, especially during the hottest hours of the day. Methods: The research methodology involves the study of the thermal performance of two traditional houses and one modern dwelling unit in Lucknow during the climatic extremes, i.e. summer and winter, by means of on-site monitoring of temperature and relative humidity. Results and discussion: We have summarized the comparative analysis of the thermal performance of traditional houses and modern houses and drawn conclusions from the factors that are responsible for providing thermal comfort. The analysis shows that the use of natural and passive techniques in the traditional buildings of Lucknow is very effective in terms of providing a thermally comfortable space, warm in the winter and cool in the summer.