The impacts of global warming and the increased frequency of heatwaves have been widely discussed. This aspect has been included in studies of urban climate, which have shown higher temperatures over cities compared to the outskirts, a phenomenon known as the urban heat island. Swedish cities such as Stockholm are constantly expanding, which may lead to further impacts on the thermal environment. Studying the effect of typologies within the city is necessary as they affect the thermal comfort to different extents. This thesis used the local climate zone classification to obtain understanding for how different summer conditions and land covers affect thermal comfort. Meteorological data provided by the land-surface model SURFEX showed how shading from vegetation and buildings had a mitigating effect during the day where buildings are densely constructed, while the latter contributed to a warming effect during the night. Proximity to water also reduced the heat stress during the day, but the stored heat is released during nighttime, disallowing the atmosphere to cool down. Tropical nights were more frequent during a longer heatwave over surfaces with high-density buildings, in proximity to water and with little vegetation, further increasing the heat stress. In order to reduce the heat stress in cities, municipalities need to take the role of micro-climates into consideration in urban planning.