In relation to the problem of supercooling for ice storage devices, a basic investigation is carried out by performing a number of experiments and a statistical analysis. In the experiments, the freezing temperature of supercooled water on a heat transfer surface is measured. It is observed that the characteristics of the surface and the cooling condition affect the freezing temperature. The probability of the initial appearance of ice within a unit surface area in a unit time interval is introduced as a function of the degree of supercooling and the surface property. Finally, a method to predict the most probable freezing temperature of supercooled water for a given cooling condition and surface property is proposed.