The characteristics of the atmospheric circulation during the winter of 2025 (from December 2025 to February 2026) are as follows. The polar vortex in the Northern Hemisphere exhibited a dipole pattern, and the circulation in the middle and high latitudes showed a 4-wave pattern. The troughs and ridges in the westerlies were significantly weaker than those in the same period of normal years. A total of 14 gale events exceeding Beaufort wind scale 8 occurred over China's offshore areas, including 9 events affected by cold air, 4 events jointly affected by cold air and extratropical cyclones, and one event jointly affected by cold air and tropical cyclones. There were 5 large-scale sea fog events over China's offshore areas, which mainly occurred in the Bohai Sea, the Bohai Strait, the Yellow Sea, the Beibu Gulf, the Qiongzhou Strait and coastal waters of the Leizhou Peninsula. A total of two tropical cyclones formed over western North Pacific and the South China Sea, and 14 tropical cyclones formed in other ocean basins worldwide. The number of days with rough sea wave exceeding 2.0 m in height over China's offshore areas was 79 d, accounting for approximately 88% of the total winter days, with 20 such rough sea wave events recorded. During this season, the sea surface temperature (SST) over China's offshore areas showed a monthly declining trend, with a more pronounced cooling in northern sea areas, and the cooling range in the East China Sea was smaller than that in the Bohai Sea and the Yellow Sea. The SST in eastern and southern sea areas of China presented a northwest-southeast gradient distribution. In winter, the temperature difference between the Bohai Sea with the lowest monthly SST and the southeastern South China Sea with the highest SST rose from 28 ℃ to 30 ℃, forming a distinct north-south thermal disparity. Positive SST anomalies prevailed across most sea areas throughout the season. The positive anomaly magnitude gradually weakened month by month in the Bohai Sea, the Yellow Sea and the East China Sea, while it intensified in the South China Sea, with local positive anomalies exceeding 2 ℃ in some regions.