Despite the growth in the global cumulative installed photovoltaic (PV) capacity, the efficiency of PV panels is greatly reduced due to dust accumulation and soiling. To enhance this efficiency, consideration must be given to the factors that affect dust deposition ranging from panel configuration to weather conditions. This research aims to determine which of those factors contribute significantly to dust accumulation and model this behavior. Numerical experiments were performed to study those factors based on a planned Design of Experiments (DOE). Dust particle size, dust amount, wind speed, wind direction, and the solar panel tilt angle are the five factors examined using computational fluid dynamics (CFD) simulations. Statistical and regression analyses were then used to determine the most significant factors and model their effect on the deposition rate. Results revealed that the dust diameter, panel tilt angle, and wind speed influence the deposition rate the most. Dust diameter is positively correlated to the dust deposition rate. Larger dust particles have a lower deposition rate as the wind velocity increases. In addition, smaller dust particles will always give the lowest dust deposition rate irrespective of the tilt angle. It was also seen that the maximum dust deposition rate occurs at a panel’s tilt angle of approximately 50 deg regardless of the wind speed or the dust particle size. The developed mathematical model shows the factors contributing to soiling and panel efficiency reduction over exposure time. This model can be used further to optimize panel cleaning frequency.