In a recent paper Krzysztofowicz (1999) has proposed twoapproaches to estimate a probability of an event (forexample, precipitation) within a period in terms offorecasted marginal probabilities of occurrence of thatevent within nonoverlapping subperiods. The approachesare analyzed and it is shown that estimators proposed arebased on some additional assumptions not presented in thedata. The principle of maximum entropy which enables oneto account for the total information available and not toinvoke any additional hypothesis is used to assess theprobability.