This is a specialized agency of the United Nations that acts as the authorized reporter regarding the state and behavior of terrestrial atmosphere, its interaction with the oceans, the climate it produces and the resulting distribution of water resources. It was created in 1950 and became the agency for meteorology (weather and climate), operational hydrology and other related geophysical sciences. Likewise, it provides the framework for the development of international cooperation in the expansion of meteorology and operational hydrology and the benefits stemming from their application.

Colombia has been a member country since January 5, 1962. The Institute of Hydrology, Meteorology and Environmental Studies (IDEAM), is the representative agency in Colombia. The World Meteorological Congress is the supreme body of the organization. Every four years, the representatives of all member states meet to define the general policy to be followed, in order to accomplish the goals of the Organization.

The headquarters are located in Geneva and it also has offices in New York and Brussels.
http://www.wmo.int/pages/index_es.html