We live on an interconnected planet. We share one Earth, with one atmosphere and one ocean. Our weather and climate and the water cycle know no national or political boundaries. International cooperation is essential. This philosophy has driven the work of the world’s meteorological community since 1873 and will guide us as we translate science into services for society for present and future generations. World Meteorological Day 2023 takes place during WMO’s 150th anniversary. It highlights past achievements, present progress and future potential - from the late 19th century telegraphs and shipping forecasts to supercomputers and space technology.