Cities are one of the major contributors of climate change. The built environment urgently needs to significantly reduce its impact on resource depletion and its CO2 emissions. At the same time, urban environments must adapt to guarantee livability and safety in increasingly frequent severe conditions. To aid this process, assessment methods and indexes have been developed to help designers and researchers investigate optimal solutions for outdoor thermal comfort. Temperature increase during summer is a growing concern also in northern European cities such as Tallinn, Estonia. This paper presents a study on the comfort conditions of the outdoor areas of the TalTech campus in Tallinn during summer and investigates the cooling potential of vegetated surfaces and trees in the local micro-climate. A parametric design workflow was developed that integrates building and climate modeling, environmental and building simulations and outdoor comfort assessment through the metrics of Universal Thermal Climate Index and Outdoor Thermal Comfort Autonomy. The results show that heat stress can be experienced on the outdoor areas of the campus. The quantity and the optimal location of vegetated surfaces and trees to provide comfort were determined through the developed algorithm. The methods and the generated vegetation patterns are presented and discussed.