The electrical conversion efficiency of large-scale photovoltaics is dependent on the operating temperature of the photovoltaic module. Therefore, if a tool for analyzing the annual electrical conversion efficiency could be developed on the basis of the climatic conditions at the system installation site, it would be effective for assessing system economy. Accordingly, an analysis method was developed in this study to determine the temperature distribution and electrical conversion efficiency of a photovoltaic module by considering the wind conditions at the installation site. Modular temperature distribution and DC electrical conversion efficiency were obtained by introducing the physical properties of the photovoltaic module, wind conditions, and climatic conditions (plane of array irradiance and ambient temperature) by using a digital three-dimensional topographic map in a heat-transfer calculation. The case analysis results suggest a high value for the power-production efficiency for low ambient temperature. However, the difference in the temperature distribution of the photovoltaic module in relation to the difference in the ambient temperature is strongly influenced by wind velocity and wind direction. Moreover, when a large-scale photovoltaic power plant is installed on a complicated mountain slope, the cooling effect is controlled so that the indraft wind velocity on the photovoltaic module decreases. Therefore, in order to maintain high electrical conversion efficiency in the photovoltaic module, the best location for installation is an airy and flat area, as much as possible. According to the case analysis, the electrical conversion efficiency of the photovoltaic module at the time of the analysis under wind condition increased 23% (maximum) compared with that without wind conditions. (C) 2014 Elsevier Ltd. All rights reserved.