Xinjiang is a typical arid and semi-arid Mountain basin system, which make the regional ecosystem extremely fragile. Studying the influence of climate on vegetation is conducive to qualitatively analyze the change trend of vegetation coverage in this region. Therefore, utilizing vegetation coverage and main meteorological elements (temperature, precipitation, relative humidity, sunshine hours) data in Xinjiang province, this paper carried out the influence of multiple meteorological elements on vegetation coverage changes, and constructed a model of the impact of multiple meteorological elements on the growing season vegetation coverage based on random forest. The model can better simulate the vegetation coverage in 2017 and 2018, with an average error of 0.027, in consequence it can well forecast whether the vegetation is high-density or low-density in this area. Correlation analysis and variable importance show that the critical meteorological factors affecting vegetation cover change are relative humidity and sunshine hours, accounting for 73% of the vegetation coverage area. The results are helpful to understand how meteorological factors affect the vegetation coverage, and then provide a theoretical reference for the construction of ecological security in Xinjiang.

Consecutive dry and wet extremes have drawn increasing attention due to their compounded social and environmental impacts, compared with isolated events. This study investigates dry–wet alternation events across China from 1961 to 2020 using the monthly standardized precipitation index (SPI). Two transition types are identified: dry-to-wet (DTW) and wet-to-dry (WTD) events. DTWs and WTDs occur most frequently in eastern China, especially over the Haihe River basin and the southern Yellow River basin. On average, DTWs exhibit longer transition durations than WTDs. Both event types have significantly increased in frequency and shortened in transition time across North China, Southwest China, and the lower reaches of the Yangtze River basin, indicating an elevated risk of abrupt hydroclimatic transitions. Autumn is the most active season for both DTW and WTD events. Over recent decades, their high-frequency regions have expanded northward, accompanied by shorter transition durations since the 2010s. Moisture budget analysis indicates that DTWs are primarily influenced by anomalous vertical moisture advection, while WTDs are driven by enhanced meridional moisture transport, especially in northern basins. These contrasting mechanisms highlight the growing instability of regional hydroclimatic conditions and emphasize the need for improved prediction and management of abrupt dry–wet transitions under a changing climate.