Solar cold storage is a method of refrigeration that utilizes solar energy instead of fossil fuels. It is eco-friendly and can provide refrigeration in remote locations where energy is limited. Underground cold storage is a popular method for storing temperature-sensitive perishable goods in a stable and regulated environment. The soil’s insulation properties maintain the proper temperature and prevent rotting, while the subterranean placement contributes to energy efficiency and reduces the facility’s carbon impact. However, literature in this regard does not consider the moisture condition of the soil to determine the amount of heat gain in the cold room. In this regard, a correlation between the thermal conductivity of the soil and the moisture content of sandy-loam soil has been developed and validated. The developed correlation is then encoded to the TRNSYS simulation program to predict the instantaneous cooling load requirement of the underground cold storage. The yearly reduction in cooling load requirement of the underground cold storage compared to aboveground cold storage was found to be ~20% and 37.8% when the cold storage unit set temperatures were kept at 5 °C and 10 °C, respectively.