This lecture explores the concept of opportunistic integrated communication and weather sensing, focusing on the CELLENMON technology. It covers topics such as the attenuation of signals, the use of commercial microwave links for weather monitoring, and the challenges and future directions of this technology. The presentation delves into the theoretical and practical aspects of using data-driven algorithms for rainfall estimation, the spatial resolution of rainfall maps, and the classification of precipitation types. The lecture also discusses the broader implications of this technology, including its potential contributions to public good and sustainability. Various projects and collaborations in this field are highlighted, showcasing the evolution and impact of opportunistic environmental sensing.