Abstract:The main characteristics of the general atmospheric circulation in May 2026 are that the Northern Hemisphere polar vortex exhibited a mono-polar distribution with intensity slightly stronger than normal. The circulation in middle-high latitudes transformed from a three-wave pattern in winter to a four-wave pattern in summer. Over the Eurasian continent, the circulation was distributed in a pattern of “two-trough-one-ridge” in the first ten days, turned to a “one-trough-two-ridge” shape in the second ten days, and then into a “two-trough-two-ridge” appearance in the last ten days. The western Pacific subtropical high was stronger and located more westward than usual. The monthly mean temperature across China was 17.2℃, 0.7℃ higher than the climatological average, ranking as the 7th highest for the same period since 1961. The monthly precipitation averaged 77.0 mm, 10% more than in the same period of normal years. During this month, four regional torrential rain events and eight severe convection processes occurred in China. The extreme nature of severe precipitation was prominent, with daily precipitation at six stations including Enping in Guangdong Province and Jingzhou in Hubei Province exceeding their historical records. On 31 May, a large-scale thunderstorm gale event occurred in Northeast China, with the peak wind speed in Suihua, Heilongjiang Province, reaching 44.3 m·s-1. At the same time, tornado event was observed in Jilin Province. In addition, two sand-dust events affected China, and the first high-temperature event of this year appeared in regions south of the Yangtze River， South China and eastern Southwest China from 25 to 29.