The study examined the effect of altitude on the performance of silicon solar cells. Solar cells are one part of renewable energy systems and claen energy source.The performance of a silicon solar cell is influenced by many factors, like temperature, altitude, humidity, air mass, wind speed and irradiance. Yet, here we intend on the effect of altitude on the performance of the silicon solar cells. Here, it worth remembering that the effect of altitude on solar cells is considered at a defined geographical place, which does not affect the sun inclination and angle. Thus, considers the efficiency of the silicon solar cell at a given location by only changing the altitude but not the location. Besides, the study considers both Photovoltaic panel and solar cells, as the effect is the same for both, i.e., the Photovoltaic panel is made of the solar cells. Atmospheric physics tells us those different metrological parameters changes as altitude changes at a given location. As one go from a bottom to a top of a mountain, altitude increases, the following parameters are changed as: temperature decreases, wind speed increases, humidity decreases, irraduiance increases, but air mass is not changing. Intrestingly, the changed parameters listed (temperature, wind speeed, humidity, and irradinace) favor towards the increase in performance of a silicon solar cell. Yet, the trend in efficiency/performamce change remains to be complicated and it will be desribed in this work. The study assesses the effect of changes of altitude on the specified metrological parmaeters one by one (based on several reserachers published work). Here, the assessed study might not be directly related to solar cells, e.g., effect of altitude on surrounding temperature. But, this will work will then connect to the device physics (e.g., effect of temperature on solar cells).. Additionally, is also considers direct study of solar cells by metrological factors, and this study will intregrate and summurise it together. As an example, according to the former studies, at the same time and at the same intensity of sunlight, the power accession of 7-12% was observed due to placement of solar panel at a particular height of 90 foot/27.432m above the datum/ground Level.Thus, based on collcted assesed data and device physics, this work will summrise the total effect of altitude on the efficency of solar cells. Key words: Solar Cell, Temperature, Efficency and Altitude