In this paper we study the wide sense stationarity of the energy of the underwater acoustic channel impulse response and we provide an estimate of the interval during which the wide sense stationarity property holds. We analyze the SPACE08 data set, which has been collected near MarthaÂ¿s Vineyard Island during October 2008. In this data set the environmental conditions such as the height of the waves and the wind direction vary significantly in time. We consider the time series recorded in four different fixed positions. This allows us to compare the results between different locations and environmental conditions.