This dataset is a supplement to the study "The open ocean kinetic energy cascade is strongest in late winter and spring" by René Schubert, Oscar Vergara, and Jonathan Gula, published in Nature Communications Earth and Environment. It includes the code for the underlying analysis and visualization in the jupyter notebook 'code_schubert_etal_2023_ncommsenv.ipynb', the data to reproduce the figures, and the monthly climatologies of the estimated scale kinetic energy transfer and of the transition scale from balanced to unbalanced flows based on JASON-3 data. The transition scale has been computed by Oscar Vergara. All the other data and code have been created by René Schubert. The analysis bases on numerical ocean simulations that have been run by Jonathan Gula.