The urban historical development of Ho Chi Minh City has reported the parallel existence of planned and spontaneous districts, even the integration or juxtaposition of both regular and irregular planned settlements found within a ward. The city expansion has been attached to the growth of the economy, population, and urbanisation. As a result, many urban blocks are characterised by distinctive spatial structures and constitutions. Sequentially, the urban climate is changing and performs variations at both the macro and micro scales, significantly affecting the human living environment. So, people’s tolerance, behaviours, and adaptation have also been adjusted to restore their comfort. The paper understood the characteristics of residential neighbourhoods in terms of their urban morphology and environmental performance. Furthermore, the study deciphered the interplay between the two features and advised on how to improve the outdoor microclimate, which is beneficial for outdoor comfort for pedestrians and a better indoor environmental condition linked through exchange between two environments. Over 60 settlements classified into seven urban types were visited and measured with environmental indices in cool and hot seasons. Outdoor climatic conditions were more pleasant in cool months. However, the onsite measurements concluded discomfort for people due to high temperatures and low winds in all seven urban types. The external microclimate was more satisfactory in neighbourhoods, which featured a regular pattern, low density, and available plants and green spaces, especially in pericentral areas. Meanwhile, the environment around unplanned settlements was difficult to predict.