This Guidance Volume II: Demonstration Cities provides an overview of the demand for such services in WMO Member countries and examples of current IUS that were designed to meet a range of urban environmental challenges in a variety of administrative settings. A survey was conducted among WMO Members in 2018 and 87 responses were received. The purpose of the survey was to judge the level of service provision in different focal areas (weather, climate, hydrology and air-quality), the extent to which users and providers collaborate, the operational status of urban services and the level of integration between the different service elements.