ORIGINAL ARTICLE Assessment of bioclimatic conditions on Crete Island, Greece Anastasia Bleta • Panagiotis T. Nastos • Andreas Matzarakis Received: 3 May 2012 / Accepted: 30 August 2013 Ó Springer-Verlag Berlin Heidelberg 2013 Abstract The objective of this study was to assess and analyze the human bioclimatic conditions of Crete Island, by applying two human thermal indices: physiological equivalent temperature (PET), derived from the Munich Energy-balance Model for Individuals human energy bal- ance model, and Universal Thermal Climate Index (UTCI), based on the Fiala multi-node model of human thermo- regulation. Human bioclimatic studies provide a frame- work for considering the effects of climatic conditions on human beings and highlighting the social/economic factors that mitigate or amplify the consequences of environmental changes. In order to estimate the thermal effect of the environment on the human body, it has been considered that the total effects of all thermal components, not only of individual parameters, should be taken into account. The climatic data (air temperature, relative humidity, cloudi- ness, wind speed) used in this study were acquired from the archives of the Hellenic National Meteorological Service, regarding ten meteorological stations in Crete Island. These data, covering the 30-year period 1975–2004, were used for the calculation of PET and UTCI in order to assess thermo- physiological stress levels. The findings of this analysis, such as bioclimatic diagrams, temporal and spatial distri- butions of PET and UTCI as well as trends and variability, will help stake holders to understand and interpret the island’s current bioclimate, in order to make any necessary adaptations and become more resilient to the foreseen climate change. Keywords Bioclimatic conditions  PET  UTCI  Crete Island Introduction The quality of life in an urban or rural environment is influenced significantly by bioclimatic conditions, both short and long terms. Bioclimatic conditions are modified due to environmental factors and the complex structure and development of urban agglomerations as well. There has been extended human biometeorological research indicat- ing the impact of urban bioclimate on human morbidity (Schwartz et al. 2004; Nastos and Matzarakis 2006; Mi- chelozzi et al. 2007), mortality (Curriero et al. 2002; An- alitis et al. 2008; Baccini et al. 2008; Hajat and Kosatky 2010; Almeida et al. 2010; Nastos and Matzarakis 2012), tourism potential and decision making (de Freitas 2003; Didaskalou and Nastos 2003; Hamilton and Lau 2005; Lin et al. 2006; Matzarakis and Nastos 2011), and urban planning (Carmona et al. 2003; Nikolopoulou and Steemers 2003; Nikolopoulou and Lykoudis 2006; Thorsson et al. 2004; 2007). Over the last years, many attempts have been made to formulate a reliable and user-friendly index for the assessment of the physiological thermal response of the human body to climatic conditions (d’Ambrosio Alfano et al. 2011), but only physiological equivalent temperature (PET) and Universal Thermal Climate Index (UTCI) seem to meet these requirements. PET is recommended for the evaluation of the thermal component of different climates by VDI Guideline 3787 (VDI 1998). PET is based on the A. Bleta  P. T. Nastos (&) Laboratory of Climatology and Atmospheric Environment, Department of Geography and Climatology, Faculty of Geology and Geoenviroment, National and Kapodistrian University of Athens, Panepistimiopolis, 15784 Athens, Greece e-mail: nastos@geol.uoa.gr A. Matzarakis Meteorological Institute, Albert Ludwigs University of Freiburg, 79085 Freiburg, Germany 123 Reg Environ Change DOI 10.1007/s10113-013-0530-7