The study analyzed the impact of weather conditions at the onset of the vegetation period determined by indicators of thermal satellite observations and phenological phenomena. Meteorological conditions including thermal, solar and snow conditions, determined on the basis of information from the ERA Interim reanalysis. The satellite data are derived from the MODIS scanner mounted on platforms TERRA and AQUA satellites. The phenological observations defined the flowering phase and the various stages of hazel pollen. During the analysis it has been found that there is a close relationship between the phases of the pollen of the hazel and the maximum, minimum and mean monthly air temperature. Statistically significant covariance was also found in the case of the date of the onset of each phase of the common hazel pollination and the dates of the onset of growing season determined by Gumiński method. A higher air temperature and thinner snow cover in the period from January to March had the highest impact on early flowering of the common hazel.