World Meteorological Day

Each year, on 23 March, the World Meteorological Organization (WMO), its 191 Members and the worldwide meteorological community celebrate World Meteorological Day around a chosen theme. This day commemorates the entry into force, on that date in 1950, of the WMO Convention creating the Organization. Subsequently, in 1951, WMO was designated a specialized agency of the United Nations System.

About WMO
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 (since 4 December 2009). The Convention of the World Meteorological Organization was signed 11 October 1947 and established upon ratification in 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.