Each year, on 23 March, the World Meteorological Organization, its 188 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. In 2009, the theme is "Weather, climate and the air we breathe".