The World Meteorological Organization (WMO) is a specialized agency of the United Nations responsible for promoting international cooperation on atmospheric science, climatology, hydrology and geophysics.

[5] The Convention entered into force on 23 March 1950, and the following year the WMO began operations as an intergovernmental organization within the UN system.

The WMO is made up of 193 countries and territories, and facilitates the "free and unrestricted" exchange of data, information, and research between the respective meteorological and hydrological institutions of its members.

[6][7] It also collaborates with nongovernmental partners and other international organizations on matters related to environmental protection, climate change, resource management, and socioeconomic development.

[8] Headquartered in Geneva, Switzerland, the WMO is governed by the World Meteorological Congress, composed of member states, which meets every four years to set policies and priorities.

[9] The WMO was established by the Convention of the World Meteorological Organization,[10] signed 11 October 1947 and ratified on 23 March 1950.

The Convention serves as the constituent treaty of the WMO, setting forth its purposes, governance, and general framework.