In this study, we analyze the performance of Photovolatic (PV) systems on hourly basis. Comparison is made between the clear day condition and the typical condition in yellow dust outbreaks in order to characterize the overall influence of the yellow dust events. The potential reduction of the solar spectral irradiance due to yellow dust events is investigated, using a clear-sky spectral radiation model (SMARTS), and the performance indices of PVs under reduced irradiance are calculated by using an analytic model representing typical photovoltaic cells.