This study presents the development of a one-dimensional thermal model to analyze the performance of an improved inclined solar still equipped with a fan and phase change material (PCM). The modeling is based on mass and energy conservation equations applied to the various components of the system, incorporating all heat transfer mechanisms as well as the processes of evaporation and condensation. The proposed model is capable of estimating the temperatures of different parts of the solar still, as well as the hourly and daily fresh water production rates. Numerical simulation of the model was carried out in MATLAB using a time step of 0.1 seconds. In this research, the model was validated over a period of three days. The results demonstrate high accuracy of the thermal model, showing that it can reliably predict the component temperatures and freshwater yield under varying conditions. The model exhibited excellent precision in estimating the temperatures of the brine and absorber plate, with root mean square error (RMSE) values below 2.2 °C. For freshwater production, the maximum deviation between the model predictions and experimental data was less than 9% in the worst case. Parametric studies revealed that selecting an appropriate melting temperature for the PCM can enhance freshwater production by up to 5%, while the PCM mass had no significant effect on the still's performance.