This study develops a numerical model to examine the weathering of oil, with a focus on emulsification in the context of marine oil spills. In marine spills, oil weathering plays a significant role as it affects the density and viscosity of the oil in water. The emulsification process affects the density and viscosity of oil, forming a water-in-oil emulsion that has a negative impact on the environment and cleanup operations. There are only limited studies that have been conducted in the literature related to oil spills in tropical oceanic conditions. Thus, current research focused on studying the oil spill behavior in tropical oceanic conditions. During this study, existing models in the literature were extensively studied to establish the different empirical and semi-empirical formulas to model the emulsification process of spilled oil. The simulation results were validated using the experimental data available in the literature. The sensitivity of the emulsification process to environmental factors was investigated using the developed model. The findings demonstrated that the ambient wind speed significantly affects the process of oil emulsion. The analysis showed that viscosity reduces when sea surface temperature increases; however, viscosity significantly increases over time as a result of evaporation and emulsification processes. Having proper numerical models to assess the oil viscosity variations and the factors influencing those changes will be key in accurately predicting the oil fate in a spill, which is the future direction of this research.