In order to develop solar still systems and increase their productivity after sunset, phase change materials (PCMs) need to be employed. The melting point is the most substantial of PCM's many variations and characteristics, which make it distinctive. In this study, white petroleum jelly stored in copper cylinders is used to enhance the daily productivity and efficiency of the system thereby. The temperature of the glass cover, the output of the distillate, and the coefficients of evaporative, convective, and radiative heat transfer all are the objects of experimental studies. White petroleum jelly as thermal energy storage (PCM) mechanisms with a low melting point (36 °C) are better used in a solar still. The study has been carried out outdoors by designing to simulate the toughest weather in November (winter start) in Shahdol, M.P. In comparison to white petroleum jelly stored in aluminum tubes, the results show that white petroleum jelly stored in copper cylinders significantly improves the distillate and system performance. Even after being stored in a copper cylinder, the thermophysical properties of the PCM have not been changed. The maximum daily productivity in winter is determined to be around 2940 ml/m2-day on clear days. However, white petroleum jelly has a lower melting point than other materials such as paraffin wax, it can be used in both summer and winter.