The thermal environment in outdoor public spaces and their level of use are strongly connected. The design of outdoor spaces, especially in urban areas, is very critical in Southern Europe due to their extended use during summertime where the urban heat island phenomenon deteriorates the microclimatic conditions. In this paper the main outcomes of outdoor spaces field surveys are presented, which were carried out in four different urban open spaces in Crete. On site measurements were implemented and a questionnaire was used in order to estimate the thermal comfort of visitors. Thermal indices like Predicted Mean Vote, Physiologically Equivalent Temperature, Standard Effective Temperature, Wet Bulb Globe Temperature are used to evaluate the features of urban microclimate and then are being compared in order to find the most suitable for the Mediterranean microclimate. This suggests another way of approach to the researcher and provides essential tools to the designer. (C) 2014 Elsevier Ltd. All rights reserved.