This contribution introduces an Airflow Zonal Model (AZM), aimed at providing a spatialized information on outdoor thermal environments at the block-scale, over daily and seasonal periods for heat stress assessment. Urban geometry is simplified using slabs aligned the orthonormal coordinate system (x, y, z). The model relies on prior steady CFD calculations, utilizing the RANS realizable k-ε turbulence model. CFD calculations are employed for predicting mass flow rates, average wind speeds, external convective heat transfer coefficients, and pressure coefficients through interpolation methods. The dynamic solution of energy and mass balances in each airzone ensures the continuity of mass and heat transfers between the outdoor environment and the building, allowing the coupling with a building model. An application of the airflow model to a theoretical case study demonstrates the applicability of this zonal model at the block scale. The results show the AZM’s capacity to replicate average velocity fields simulated by CFD, offering a comprehensive solution for forecasting mass flow rates, convective heat transfer.