World Meteorological Day is celebrated every year on 23 March. This Day commemorates the entry into force on that date in 1950 of the Convention that created the World Meteorological Organization (WMO). For the year 2006, the theme ‘Preventing and mitigating natural disasters’ was chosen for the celebration, in recognition of the fact that 90% of all natural hazards are related to weather, climate and water and of the vital role played by WMO and the National Meteorological and Hydrological Services (NMHSs) in contributing to prevention, preparedness and mitigation of natural disasters, as well as those arising from environmental emergencies.