The widespread availability of open datasets in cities is transforming the way urban energy systems are planned, simulated, and visualized. In this paper, a cross-scale approach is pursued to better understand the reciprocal effects between building energy performance, the urban climate, and urban dwellers’ indoor and outdoor thermal comfort. On the one hand, monthly building electricity and gas demand data at the parcel level was collected, along with hourly weather station data at the urban scale. On the other hand, a longitudinal experiment was carried out in which 22 participants wore smartwatches for 4–6 weeks and filled out hourly micro surveys on their activities, location, and thermal comfort. In addition to survey responses, the smartwatches collected participants’ physiological data and location throughout the period of the study. The project was conducted in Seoul, South Korea, the highest-ranked Asian country in open data readiness, implementation, and impact. This paper reports on the data collection effort and provides some preliminary analysis of the results. The work carried out is expected to help develop methodologies for the convergence of district-scale and occupant-scale data in urban areas. A number of expected applications are proposed, including urban-scale studies on the impact of urban form on the local climate and building energy performance, district-to-building-scale building energy simulations accounting for occupant thermal comfort-related behaviors, and district-scale analyses of occupants’ outdoor thermal comfort and its relationship with location and wayfinding in urban areas.@en