World Metrology Day is celebrated annually on May 20th to commemorate the signing of the Metre Convention in 1875, which laid the foundation for global collaboration in measurement science. Metrology—the science of measurement—is essential in everyday life, from ensuring accurate timekeeping and reliable healthcare diagnostics to supporting scientific research and international trade.Each year, the day highlights a specific theme reflecting current global challenges or innovations in measurement. It serves as a reminder of the critical role that precise, standardized measurements play in advancing technology, safety, and sustainability worldwide.