Energetic complementarity is a subject that has been holding more and more attention from researchers in recent years, being a concept that can be applied both in energy planning stages and in phases of operation of energy systems based on renewable energy resources. The complementarity between two renewable sources of energy has three components: time-complementarity, energy-complementarity and amplitude-complementarity, and can be determined between raw energy availabilities or between energy generated by power plants. Complementarity can be evaluated between two renewable resources in the same place or between two renewable resources in different places and these two types can be denominated respectively as temporal and spatial complementarity. This method allows simplified evaluation of the energy complementarity between two renewable resources by comparing basic parameters obtained from series of monthly average values that characterize these resources. Finally, an application example clarifies the application of the method. •The method allows a quick and visual but expeditious evaluation of energetic complementarity.•This method provides a reference value for the application of more complex methods for evaluation of complementarity.•Monthly average data allows the comparison of renewable resources with different characteristics of intermittency and variability.