Abstract—The continual search for new sources of renewable energy has resulted in the progress of floating solar photovoltaics (FSP). Since FSP system design and implementation are still in their early stages, efficiency, output and performance studies of FSP systems are not adequately acknowledged. FSPs operate on water; hence their performance differs from that of their equivalent land-based photovoltaics (LBP). The effect of water and humidity on the performance of FSP systems is not adequately discussed in the literature. Therefore, this paper investigates the effect of water – especially humidity – on the parameters and overall operation of FSP systems. For this purpose, an experiment is conducted with an FSP module, and the data obtained – over five months – are compared with similar LBP modules to determine the impact of water on the performance of the FSP system. The obtained results show that the FSP system is cooler than the LBP system by 7 ℃. The relative humidity (RH) is found to be higher in the FSP system, and this impacted the performance ratio (PR) of the FSP system. Moreover, it is observed that – despite the fact that RH has an influence on the PR of the FSP system – the FSP system outperforms the LBP system in terms of energy output.