Standard test conditions (STC) of photovoltaic (PV) modules are not representative of field conditions; PV module operating temperature often rises up to 30 degrees C above STC temperature (25 degrees C), causing a performance drop of 0.5%/degrees C for crystalline silicium modules. Normal operating cell temperature (NOCT) provides better estimates of PV module temperature rise. It has nevertheless to be measured: moreover NOCT wind speed conditions do not always fit field conditions. The purpose of this work is to model average PV module temperature at given irradiance levels as a function of meteorological parameters and PV module implementation. Thus, no empirical knowledge of PV module thermal behaviour is required for energy rating basing on irradiation distributions over irradiance levels. (C) 2008 Published by Elsevier Ltd.