In order to make CPV (Concentrated Photovoltaic) technology a real alternative to conventional generation of electricity, it is necessary to gain knowledge about its real outdoor operation by using a wide experimental basis. This basis makes it possible to analyze the electrical performance of these systems, and to obtain models to predict it. In this work, a prediction model is proposed. It calculates the maximum power delivered by CPV modules under previously known specific atmospheric conditions. To create this model, an experimental campaign was carried out in Jaen, Spain, from May 2012 to April 2013. In this campaign there were periodical measurements of the electrical parameters delivered by a CPV module, as well as the environmental variables that influence its performance - direct normal irradiance and its spectral distribution through the SMR (Spectral Matching Ratio) index, ambient temperature and wind speed. The proposed model was validated with one of the most frequently used commercial CPV modules in the market, but it can be used to predict the electrical performance of any other CPV module with similar constructive characteristics. An error within the range [3.98-5.27], in percentual terms, was obtained in the validation process performed to test the accuracy of the model. (C) 2014 Elsevier Ltd. All rights reserved.