Indonesia has a target of achieving 23% of renewable energy share in total energy mix in 2025. However, as commonly observed across developing economies, Indonesia also does not have accurate and comprehensive database of renewable energy potentials, especially wind energy. Therefore, this article aims to assess the theoretical potential of wind speed and to visualize the wind speed by province based on wind map using GIS for the entire Indonesia. Our assessment integrates advanced analytical techniques, i.e., Weather Research and Forecasting (WRF) model, method geographic information system (GIS), Newtonian relaxation assimilation technique, and Variational Analysis Method (VAM). The robustness of our analysis is confirmed by using high resolution data from the National Aeronautics and Space Administration (NASA) database and Cross-Calibrated Multi-Platform (CCMP) Reanalysis satellite data. Wind resource measurement data in Jayapura, Bantaeng and Sukabumi sites are used to validate the modelling results. The biases of the modelled data are 0.324, 0.368, and 0.324 in Jayapura, Bantaeng and Sukabumi respectively. This conclusion has two global implications. First, this study shows the WRF method is a feasible option to estimate wind speed data in developing countries commonly lacking meteorological stations to measure the wind energy resources. Second, the yearly wind mapping by province level produces mean wind speed map that is a useful information to indicate the profile of wind energy resource as the input for the wind energy system planning. We then match the wind energy potentials with other factors influencing wind warm feasibility, e.g., renewable energy tariffs, and parameters of power system flexibility.