Cloud organization plays key roles in Earth’s energy budget and cloud–climate feedbacks. While previous studies have primarily focused on cloud radiative effects and moisture variability, the relationship between elevated humidity and aerosols in the vicinity of clouds remains relatively underexplored, particularly on the mesoscale. Enhanced humidity near clouds promotes aerosol hygroscopic growth, coexists with optically thin cloud features, and is subject to complex three-dimensional radiative effects. Together, these processes define the cloud transition zone (CTZ), which plays an important role in modulating Earth’s radiation budget. Here, we link cloud organization, driven by moisture aggregation, to CTZ structure by examining how mesoscale cloud patterns organize aerosol optical depth (AOD) and how CTZ properties vary across different cloud morphologies. We combine satellite observations with airborne lidar measurements from the EUREC4A field campaign to resolve the vertical structure of aerosol–cloud-radiation interactions at high resolution. Large-eddy simulations are used to further investigate the underlying processes. Our results highlight the role of mesoscale dynamics in shaping aerosol–cloud–radiation interactions and their implications for Earth’s energy balance.