The subject of this research is a long-term assessment of the dynamics of vegetation quality in the Spačvan basin from 1984 to 2023. The goal is to determine how and to what extent certain climatic factors affect the state of vegetation. The research was conducted using remote sensing methods, by analysing satellite images from the LANDSAT and Sentinel missions. The area of interest of this research is the Spačvan basin, which covers an area of 43,519 hectare. The Google Earth Engine platform was used for data collection, processing and analysis. The open source software QGIS and Microsoft Excel were used to display the data. NDVI values were measured for the period of time from 1984 to 2023, from which is evident that despite the highlighted climate parameters, the value of the index is increasing. NDVI data were extracted for the six-year period from 2018 to 2023, from which the beginning and end of the phenological cycle were estimated. These estimated results were then compared with the results obtained using an algorithm that calculates the beginning and end of the phenological cycle. It was established that the phenological cycle oscillates for one month on average, while in the previous year, 2023, has oscillated for two months. A classification using the supervised CART (Classification and Regression Tree) method was also carried out, for every 5 years from 1984 to 2023. In addition, two more detailed analyzes were carried out for the period before and after the flood in 2014, and before and after the storm in 2023. Overall, an increase in temperature and a decrease in precipitation affect the phenological cycle, but the effect is visible for a short period of time. A greater threat is created by extreme weather conditions such as floods and storms, which are also effects of climate change.