The thermodynamics of nucleation of a pure vapor is investigated in an isolated system where the heat of condensation causes an increase of the temperature. The entropy of nucleation is calculated in the system composed of a number of clusters having identical size. In recent work only the influence of temperature on the internal energy and the entropy is considered in a simple manner, In this Letter the dependence of surface tension on temperature is introduced. No principal differences could be observed compared to the use of constant surface tension but the numerical values of the entropy of nucleation differ.