Free Space Optical Communication has been developed to cover the longer distances with the growing needs of high speed. It is a data transmission technology from one point to another point by using laser beam carrying information in free space. Multiple transmitters/receivers (TX/RX) are used to improve the performance and quality of Free Space Optics (FSO) communication system under different weather conditions. This paper analyzes the performance of multiple transceivers system by the received power level (PR), Q factor and bit error rate (BER) under clear, fog and haze conditions. From the measured data is possible to calculate visibility which is the main factor for quality and estimation for the availability and reliability of FSO link. The Free Space Optical link was modelled and simulated using a commercial optical system simulator named OptiSystem by Optiwave.