In urban planning, sustainability is often synonymous to urban livability. Urban livability seeks to improve living conditions of current and future outdoor users and hence it has become a key priority for cities authorities. Melbourne, as the world second most livable city, sets out to improve its urban life quality through various policies and initiatives. One area of improvement is the creation of sustainable outdoor spaces that provides comfortable thermal conditions for its residents. The relevant strategies to create such spaces are supported by the knowledge of human thermal comfort requirements, particularly during the summer thermal conditions. Hence, this study aims to develop comprehensive thermal comfort benchmarks for Melbourne during the summer. This study builds on 4717 subjective survey responses collected in seven urban environments with different settings. Data collection was performed in Melbourne's summer from 2012 to 2015. Physiological Equivalent Temperature (PET) was used to predict thermal comfort conditions. The results were based on four thermal comfort measures (neutral temperature, preferred temperature, acceptable thermal range and thermal comfort range). The analysis' outcomes suggested that Melbourne's summer acceptable thermal range is between 11.3 °C and 20.3 °C, the preferred temperature value is 21.5 °C, the neutral temperature value is 16.1 °C. Furthermore, PET index was calibrated against thermal responses collected from the surveys. The results would help to inform policies aiming to create sustainable outdoor spaces that are pleasant to outdoor users in Melbourne. •Analytical techniques affect the values obtained for outdoor thermal benchmarking.•The thermal comfort benchmarks inform design strategies to create comfortable outdoor spaces within cities.•Summer preferred PET (21.5 °C) is higher than neutral PET (16.1 °C).•Summer acceptable thermal range is between 11.3 °C and 20.3 °C (PET) in Melbourne.•Further studies should cover other comfort requirements such as visual and acoustics.