The characteristics of the atmospheric circulation during the winter of 2025 (December to February of the following year) are as follows，the northern hemisphere polar vortex exhibited a dipole pattern, and the circulation in the middle and high latitudes showed a three-wave pattern. The troughs and ridges in the westerlies were significantly stronger than those in the same period of normal years.A total of 14 gale events exceeding Beaufort scale 8 occurred over China’s offshore areas, including 9 events influenced by cold air, 4 events jointly affected by cold air and extratropical cyclones, and 1 event jointly affected by cold air and tropical cyclones.There were 5 large-scale sea fog events over China’s offshore areas. Sea fog mainly occurred in the Bohai Sea, Bohai Strait, Yellow Sea, Beibu Gulf, Qiongzhou Strait and coastal waters of the Leizhou Peninsula.A total of 2 tropical cyclones formed over the Northwest Pacific and the South China Sea, and 14 tropical cyclones formed in other ocean basins worldwide.The number of days with rough seas exceeding 2 meters in height over China’s offshore areas was 79 days, accounting for approximately 88% of the total winter days, with 20 such rough sea events recorded.During winter, the sea surface temperature (SST) in China’s offshore waters showed a gradual decreasing trend, with a more significant cooling in the northern waters. The cooling amplitude of SST in the East China Sea was smaller than that in the Bohai Sea and the Yellow Sea.The SST in the eastern and southern sea areas exhibited a northwest-southeast oriented gradient distribution. The monthly temperature difference between the Bohai Sea (with the lowest SST) and the southeastern South China Sea (with the highest SST) increased from 28℃ to 30℃ in winter, showing an obvious north-south temperature contrast.