World Metrology Day Date in the current year: May 20, 2024

World Metrology Day World Metrology Day is an annual global observance that commemorates the signing of the Metre Convention on May 20, 1875. The Convention was crucial for the development and implementation of the metric system.

The Metre Convention, also referred to as the Treaty of the Metre, was signed by representatives of seventeen nations. As of 2014, it includes 56 member states, 41 associates, and 4 international organizations. The Convention created three main metrology organizations: the General Conference on Weights and Measures, the International Committee for Weights and Measures, and the International Bureau of Weights and Measures.

World Metrology Day (WMD) is coordinated jointly by the International Organization of Legal Metrology (OIML) and the International Bureau of Weights and Measures (BIPM). It aims to increase awareness of the importance of global collaboration in the science of measurement and the worldwide uniformity of measurement.

Every year, a new theme for the day is chosen. For example, the 2015 theme was “Measurements and Light”. It was chosen to help promote the UNESCO International Year of Light and Light-based Technologies. The promotional material related to the current year's WMD topic can be downloaded from the World Metrology Day official website,

Remind me with Google Calendar


International Observances


World Metrology Day, international observance, global observance, Metre Convention, metric system