Abstract:Looking back the sixty years of glorious history, the World Meteorological Organisation (WMO) was established with confidence in its contribution to human security and welfare. Over the past 60 years, WMO and its Members have created and evolved standardized global observing networks, together with free and unrestricted exchange of data and products policy and capability, laid the solid foundation for WMO Members to meet the ever growing challenges and requirements of an increasingly complex society. Global observations strongly rely on international cooperation, which has been the hallmark of WMO. World Weather Watch, itself a unique product of international cooperation and networking, touched every nation and enabled the global standardized observations and exchange of real time data across frontiers. The paper firstly reviews the evolvement of the World Weather Watch Global Observing System (GOS), a testament to WMO and its Members that the unique global system for which they have been responsible has so significantly contributed to the understanding of our world and its environment. The second section describes the Rolling Review of the Requirements process, i.e. how WMO observing capability can meet the user requirements, which gives excellent guidance for the observing system development. The third section gives the description of the Vision for the GOS in 2025, explaining the key development components of the future GOS. The fourth section elaborate the WMO new initiative: WMO Integrated Global Observing System (WIGOS), an integrated, comprehensive and coordinated observing system to satisfy in a cost effective and sustained manner the evolving observing requirements of WMO Members and programmes for their weather, climate, water and related environmental services and will enhance coordination of WMO observing systems with those of partner organizations for the benefit of society.