The impact of calibration conditions on the transferability of conceptual hydrological models under stationary and nonstationary climatic conditions

•A longer calibration period is required for catchments with nonstationary rainfall-runoff relationships to achieve stable simulations.•With the increase in the length of the interval between the calibration and transfer periods, the transferability of the model decreases gradually.•When forecasting runoff under nonstationary rainfall-runoff relationships, the closeness of the total rainfall amount between calibration and transfer periods is more important than the similarity in rainfall processes.