This technical note discusses the Turc-Budyko nondimensional graph, a widely used nondimensional representation relating long-term actual evaporation to precipitation and potential evaporation. Since long-term actual evaporation cannot be directly measured, it is usually derived from catchment-scale hydrological water balance. We show that for this reason, the common interpretation of the nondimensional graph is ambiguous, and we suggest giving up this classic representation and adopting instead one where actual evaporation is replaced by streamflow.