Abstract:The main characteristics of the general circulation in May 2025 are that the polar vortex in the Northern Hemisphere was partially mono polar with stronger intensity than usual. The circulation transformed from a three wave pattern in winter into a four wave pattern in summer. The western Pacific subtropical high was stronger, located more westerly than in normal years, while the south branch trough was weaker than usual. The South China Sea summer monsoon erupted in the 6th pentad (29 May) of May, 10 days later than in normal years. The monthly average temperature across China was 17.3℃, 0.8℃ higher than normal, so it was recorded as the third highest for the same historical period since 1961. The monthly average precipitation was 77.6 mm, 10% more than normal. During this month, six torrential rain and severe convection processes occurred in China, with precipitation at many stations breaking their historical extremes, causing floods and secondary geological disasters in Guizhou, Guangxi, Guangdong, Hunan, Jiangxi provinces and other regions. On 4 May, thunderstorm gale at speed of 44.7 m·s-1 was monitored in Qianxi City, Guizhou Province. On 8 May, EF1 tornadoes occurred in Qidong County and Liling City, Hunan Province. In additionThe main characteristics of the general circulation in May 2025 are that the polar vortex in the Northern Hemisphere was partially mono-polar with stronger intensity than usual. The circulation transformed from a three-wave pattern in winter into a four-wave pattern in summer. The western Pacific subtropical high was stronger, located more westerly than in normal years, while the south branch trough was weaker than usual. The South China Sea summer monsoon erupted in the 6th pentad (29 May) of May, 10 days later than in normal years. The monthly average temperature across China was 17.3℃, 0.8℃ higher than normal, so it was recorded as the third highest for the same historical period since 1961. The monthly average precipitation was 77.6 mm, 10% more than normal. During this month, six torrential rain and severe convection processes occurred in China, with precipitation at many stations breaking their historical extremes, causing floods and secondary geological disasters in Guizhou, Guangxi, Guangdong, Hunan, Jiangxi provinces and other regions. On 4 May, thunderstorm gale at speed of 44.7 m·s-1 was monitored in Qianxi City, Guizhou Province. On 8 May, EF1 tornadoes occurred in Qidong County and Liling City, Hunan Province. In addition, there were five sand-dust events affecting northern China during this month, which are noticeably more than the average for the same period from 2000 to 2024. , there were five sand dust events affecting northern China during this month, which are noticeably more than the average for the same period from 2000 to 2024.