The article presents the results of a study of the spring development of the common bird cherry during the Single Phenological Day on May 15 in the Sverdlovsk region for 2012-2023. The study of the seasonal state of the species using the descriptive method made it possible to determine the geographical patterns of the onset of phenological phases and the rate of movement of the phenomenon in space within natural zones and subzones, depending on environmental factors. Earlier development of bird cherry in the south-east and south-west of the region was revealed, and then the front of the phenomenon moves to the north and northwest. The differences between the northern and southern regions of the territory, on average, are 6-7 points. As a result of observations, a characteristic of the seasonal development of an object indicating the state of natural complexes in a brief mathematical form was obtained. The maximum advance of development was revealed in the forest-steppe zone of the Russian Plain and Western Siberia within the boundaries of the studied region. In the mountainous regions of the region, phenomena occur with a noticeable lag of 6 points compared to the plains. The speed of the phenomenon in different subzones ranges from 0.8 to 3 points / 100 km. The experience of this kind of long-term research for other regions of the country can help to identify trends in the influence of climate change on the adaptation mechanisms of individual plant species- phenoindicators.