This study presents a 2-years performance assessment of a 2.18 kWp grid-connected PV (photovoltaic) system, installed in the premises of the Technical University of Crete, Chania; important normalized parameters such as yields, losses and efficiencies are calculated and related to the local climatic characteristics. The scopes of this paper are: (i) the quantification of the effect of high temperature conditions on the electrical performance of a thin film PV system; (ii) the verification and comparison amongst the existing empirical models used to estimate PV frames operating temperature emphasizing on the accuracy of their predictions; (iii) the development of a new customized empirical model in order to determine the PV frames operating temperature, under real field conditions. The output provides safe estimates and information about the potential improvements in order to create small and large scale thin film PV installations in areas with similar climatic characteristics such as the Mediterranean coastal areas. (C) 2015 Elsevier Ltd. All rights reserved.