The characteristics of the atmospheric circulation in the Northern Hemisphere in winter 2024 (from December 2024 to February 2025) were as follows. The polar vortex was characterized by a dipole type, and the circulation in the middle and high latitudes had a three-wave distribution. There was a significantly positive anomaly in the high pressure ridge in Siberia, and the ridge was stronger than the annual average, which was conducive to the accumulation of cold air. The East Asian large trough had a weak negative anomaly, and the trough was stronger than the annual average, which helped to guide the cold air southward. One tropical cyclone was generated in western North Pacific and the South China Sea, and 15 tropical cyclones were generated in other oceans. There were 11 gale processes of Beaufort wind force scale 8 or above in the offshore waters of China, including 9 processes produced by cold air, one process by cold air and extratropical cyclones and one process by cold air and typhoon. The number of days with large waves above 2.0 m in the offshore waters of China was 54, accounting for about 60% of the total number of days in winter. There were 4 relatively obvious sea fog processes in the offshore waters of China. In winter 2024, China’s offshore waters showed an obvious cooling trend, and the cooling range of the northern waters was significantly greater than that of the southern waters. The sea surface temperature (SST) of China’s offshore waters in December 2024 was generally higher than that of the normal years, while the SST from January to February 2025 was generally lower than usual.