World Meteorological Organization


World Meteorological Organization


WMO flagWMO flag


The World Meteorological Organization (WMO) is an intergovernmental organization with a membership of 191 Member States and Territories. It originated from the International Meteorological Organization (IMO), which was founded in 1873. Established in 1950, WMO became the specialised agency of the United Nations for meteorology(weather and climate), operational hydrology and related geophysical sciences. It has its headquarters in Geneva, Switzerland, and is a member of the United Nations Development Group. The current Secretary-General is Petteri Taalas. The current president is David Grimes. The WMO is a specialised agency of the United Nations. Its purpose is to facilitate international cooperation in the establishment of networks of stations for making Meteorological, hydrological and other observations; and to promote the rapid exchange of meteorological information, the standardization of meteorological observations and the uniform publication of observations and statistics. It also furthers the application of meteorology to aviation, shipping, water problems, agriculture and other human activities, promotes operational hydrology and encourages research and training in meteorology.

The World Meteorological Organization coordinates global scientific activity to allow increasingly prompt and accurate weather information and other services for public, private and commercial use, including international airline and shipping industries. WMO's activities contribute to the safety of life and property, the socio-economic development of nations and the protection of the environment.

Within the United Nations, the Geneva-based organization provides the authoritative scientific voice on the state and behaviour of the Earth's atmosphere and climate. Members are grouped in six regional associations (Africa, Asia, South America, North and Central America, South-West Pacific and Europe). Each of them meets every four years to coordinate meteorological and operational hydrological activities within their Region. Visit the WMO web site for comprehensive information.


History of WMO

The International Meteorology Organization (IMO), as a non-governmental organization, served the cause of international meteorology well for about three-quarters of a century and that governments and meteorologists alike were generally well satisfied with such an arrangement. Towards the mid-1930s, however, it was becoming increasingly evident, at least to most meteorologists, that such a status for the focal point of international meteorology was incompatible with the importance which meteorology was at that time in the context of the vast economic and technological developments being made. By 1939, a draft of a new World Meteorological Convention (the Berlin Draft) had been prepared but further action on its approval was inevitably delayed by World War II. Some further progress was, however, possible - even during this difficult period - as the Secretariat was transferred to a neutral country, Switzerland, in 1939, shortly after the Berlin meeting. 

The changed – and exciting – meteorological world which existed after the war was evident in the agenda for the Conference of Directors meeting which took place in Washington in September 1947. The 400 resolutions reflected the wide range of topics that had been considered at the meetings of the technical and regional commissions in Toronto the previous month – codes, units, diagrams, symbols, instruments, methods of observation, station networks, telecommunications, the safety of air navigation, climatological statistics, publications, documents, education, professional training, meteorological research, legal issues and administrative matters. Moreover, relationships between IMO and the International Civil Aviation Organization, the International Telecommunication Union and the International Ice Patrol had been discussed, too. But the issue of greatest importance to IMO after the war was its status and structure.

Endeavours to resolve the matter began as early as February 1946, when the Conference of Directors asked the International Meteorological Committee to prepare a new IMO constitution, which would make the Organization an inter-governmental body. At the same time, the Committee was asked to review the composition and functions of the technical commissions and consider how the International Meteorological Organization might become associated with the newly-formed United Nations without compromising IMO’s independence and character. The Berlin Draft as revised by Drs Hesselberg and Swoboda during the war was used as a basis for the new Convention.

The task of drafting the Convention was carried out at the meeting of the International Meteorological Committee held in Paris in July 1946. After much discussion, the so-called Paris Draft, 1946 was adopted – a draft World Meteorological Convention with two annexes, one containing draft General Regulations, the other draft Technical Regulations. These three drafts were then submitted to national meteorological services and their governments for perusal.

Comments were considered at the Washington meeting of the Conference of Directors, along with four new drafts of the Convention, submitted by Canada, France, the United Kingdom and the United States. Eventually, after many disagreements had been settled and concerns over the independence and worldwide character of the new organization had been allayed, the World Meteorological Convention was approved unanimously and a resolution adopted that the new organization should seek affiliation with the United Nations. 


The Signing of the Convention and the Birth of WMO

The World Meteorological Convention was signed on 11 October 1947 and came into force on 23 March 1950. In the interim, the work of the International Meteorological Committee continued – in particular by making sure the many resolutions and recommendations of the Washington meeting were implemented. The Committee also secured recognition for itself by the United Nations as the preparatory body for the new organization and accordingly took part in relevant UN activities. The last meeting of IMO Conference of Directors was held in Paris in March 1951 and IMO formally became the World Meteorological Organization on the 17th March 1951. 


The organization

The World Meteorological Organization (WMO) is a specialized agency of the United Nations. It is the UN system's authoritative voice on the state and behavior of the Earth's atmosphere, its interaction with the oceans, the climate it produces and the resulting distribution of water resources.

WMO has a membership of 191 member states and territories, as of February 2014. The Convention of the World Meteorological Organization was signed 11 October 1947and established upon ratification on 23 March 1950. WMO became the specialized agency of the United Nations in 1951 for meteorology (weather and climate), operational hydrology and related geophysical sciences. It originated from the International Meteorological Organization (IMO), which was founded in 1873.

The WMO hierarchy:

  • The World Meteorological Congress determines the policy of WMO and meets every four years. Each Member country is represented by a Permanent Representative with WMO. The Permanent Representative should be the director of the National Meteorological or Hydrometeorological Service.
  • The Executive Council (EC) implements Congress decisions and meets once a year.
  • Six regional associations for addressing regional concerns (see the section on regional associations, below)
  • Eight technical commissions provide technical recommendations for WMO and the national services.
  • The secretariat headed by the Secretary-General coordinates the activities of WMO with a regular staff of more than 250 employees.



The World Meteorological Organization provides a framework for international cooperation in the development of meteorology and operational hydrology and their practical application.

Since its establishment, WMO has played a unique and powerful role in contributing to the safety and welfare of humanity. Under WMO leadership and within the framework of WMO programs, National Meteorological and Hydrological Services contribute substantially to the protection of life and property against natural disasters, to safeguarding the environment and to enhancing the economic and social well-being of all sectors of society in areas such as food security, water resources and transport.

The WMO and United Nations Environment Programme (UNEP) jointly created the Intergovernmental Panel on Climate Change (IPCC). It is also directly responsible for the creation of the Global Atmosphere Watch (GAW). The IPCC has received the Nobel Peace Prize in 2007 "for their efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change."

WMO promotes cooperation in the establishment of networks for making meteorological, climatological, hydrological and geophysical observations, as well as the exchange, processing and standardization of related data, and assists technology transfer, training and research. It also fosters collaboration between the National Meteorological and Hydrological Services of its Members and furthers the application of meteorology to public weather services, agriculture, aviation, shipping, the environment, water issues and the mitigation of the impacts of natural disasters.

WMO facilitates the free and unrestricted exchange of data and information, products and services in real- or near-real time on matters relating to safety and security of society, economic welfare and the protection of the environment. It contributes to policy formulation in these areas at national and international levels.

In the specific case of weather-, climate and water-related hazards, which account for nearly 90% of all natural disasters, WMO's programs provide vital information for the advance warnings that save lives and reduce damage to property and the environment. WMO also contributes to reducing the impacts of human-induced disasters, such as those associated with chemical and nuclear accidents, forest fire and volcanic ash. Studies have shown that, apart from the incalculable benefit to human well-being, every dollar invested in meteorological and hydrological services produces an economic return many times greater, often ten times or more.

WMO plays a leading role in international efforts to monitor and protect the environment through its programs. In collaboration with other UN agencies and the National Meteorological and Hydrological Services, WMO supports the implementation of a number of environmental conventions and is instrumental in providing advice and assessments to governments on related matters. These activities contribute towards ensuring the sustainable development and well-being of nations.

WMO publishes the International Cloud Atlas, the international standard cloud atlas since 1896.


Meteorological codes

In keeping with its mandate to promote the standardization of meteorological observations, the WMO maintains numerous code forms for the representation and exchange of meteorological, oceanographical, and hydrological data. The traditional code forms, such as SYNOPCLIMAT and TEMP, are character-based and their coding is position-based. Newer WMO code forms are designed for portability, extensibility and universality. These are BUFR, CREX, and, for gridded geo-positioned data, GRIB.


World Meteorological Day

WMO seat in Geneva shared with theGICHD, the GCSP and the Group on Earth Observations

WMO buliding

WMO member


  • World Meteorological Day is held annually on 23 March.

Awards and prizes

WMO conference on climate prediction and information for decision-making

World Climate Conference-3 (WCC-3) was held from 31 August to 4 September 2009 in Geneva, Switzerland, under the auspices of WMO. Its goal was to address advancements in seasonal to multi-decadal climate predictions and to spur their applications to decision-making in socio-economic sectors, including food, water, energy, health, tourism and development sectors. The Conference aimed to contribute to the achievement of the United Nations Millennium Development Goals and broader UN climate goals through support for climate adaptation.



As of February 2014, member states of the organisation include 183 of the 193 UN members, the Cook Islands and Niue, for a total of 185 member states. Additionally there are 6 member territories, listed below.

There are 10 states that are members of the United Nations, but not of the WMO. These are: Andorra,Equatorial GuineaGrenadaLiechtensteinMarshall IslandsNauruPalauSaint Kitts and NevisSaint Vincent and the Grenadines and San Marino; the most populous of these countries is Equatorial Guinea, with nearly 700,000 inhabitants. Non-members of either organisation include the Vatican City and thestates with limited recognition.

The six member territories are: the British Caribbean Territories (joint meteorological organisation and membership), French Polynesia, Hong Kong, MacauCuraçao and Sint Maarten (joint meteorological service and membership), and New Caledonia. Below is a table of all members with admission dates.


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