From a series of 83 daily heat balances for the lake la Godivelle (France), daily estimates of the rate of heating S (or variation in the heat content) of the lake are analysed by the methods of Edinger et al. (1968), Keijman (1974) for equilibrium temperature. This enables the calculation procedure and the formulation of the exchange coefficient K, and the equilibrium temperature Te, to be distinguished which give the best estimate of the rate of heating. In addition the data are used to describe the daily and seasonal behaviour of K and Tefor the summer and autumn stratification phases of the lake.