Why does South Korea use China's weather forecast?

South Korea is surrounded by the sea on three sides, and is deeply influenced by the humid air current of the ocean, so it has a subtropical monsoon climate. China belongs to the Asia-Europe plate, which has a huge sea-land difference with the Pacific plate, resulting in a diverse monsoon climate. The higher the latitude, the weaker the monsoon intensity. At the same latitude, the monsoon intensity in the ocean is greater than that in the inland.