The Basque Meteorology Agency is conducting an initiative to improve the collection, management and analysis of weather information from a large array of sensing devices. This chapter presents works carried out in this context proposing the application of 3D geographical visualization and image processing for the monitoring of meteorological phenomena. The tools described allow users to analyze visually the state of the atmosphere and its interaction with the topography, and process live outdoor images to automatically infer weather conditions. This kind of systems can be applied in the surveillance of other environmental events and enable better decision making for several purposes, including important issues related with environmental security.