From https://wmo.int/world-meteorological-day

World Meteorological Day

Every 23 March, the World Meteorological Organization commemorates the coming into force of the Convention establishing the World Meteorological Organization on 23 March 1950.

It showcases the essential contribution of National Meteorological and Hydrological Services to the safety and wellbeing of society and is celebrated with activities around the world. The themes chosen for World Meteorological Day reflect topical weather, climate or water-related issues.

The theme for World Meteorological Day 2024 is “At the frontline of climate action”.