World Metrology Day is an annual celebration of the signature of the Metre Convention on 20 May 1875 by representatives of seventeen nations. 

In 2000, SADCMET designed a “WMD poster" to send to the NMIs of the (then) 14 member states to create awareness during planned events and media campaigns. The initiative was so well received, that the BIPM and BIML adopted the initiative, and has been officially running the process from 2006, by facilitating the design and global distribution of the annual poster. Each year a regional metrology organisation is asked to develop the poster, based on the chosen theme. The annual theme is jointly chosen by the International Bureau of Weights and Measures (BIPM) and the International Bureau for Legal Metrology (BIML), and is announced towards the end of the year for implementation in the following year. They consider several inputs such as the themes adopted by the international scientific community and newsworthy metrology topics.

The day is usually commemorated with events, conferences, workshops, media features etc.  This year however, COVID-19 has forced the metrology community to resort to virtual celebrations. The NMISA has decided to publish an electronic information campaign that includes video messages and poster offerings from previous years in celebration of World Metrology Day 2020.