Purpose. To establish the level of formation of winter barley yield depending on weather conditions during the gro­wing season in the Forest-Steppe zone of Ukraine. Methods. Field investigations, ANOVA, variance and correlation analysis. Results. Positive correlation was revealed between yield and the duration of the vegetation (r = 0.54) and especially “heading–maturation” period (r = 0.76). Moderate positive correlation was established between yield and mean daily air temperature during the period from termination to resumption of vegetation (r = 0.44), and strong negative one – between yield and mean daily air temperature during hea­ding to maturation period (r = -0.77). Positive correlation was observed between yield and rainfall amount during the period from vegetation resumption to heading (r = 0.30). In general, during the growing season the correlation was weak (r = 0.16). For the period of “heading–maturation” low nega­tive value (r = -0.11) was fixed. This was due to heavy precipitations, especially torrential rains, which in some years have caused lodging of plantings resulted in yield decrease. Conclusions. Under the conditions of Forest-Steppe zone of Ukraine, fluctuations in temperature and water regimes are responsible for significant variability in growing season duration and yield of winter barley. Optimal amount of precipitation (close to long-time annual average) and their uniform distribution throughout growing season is the most favorable for obtaining high yield. “Heading–maturation» period is responsible for the formation of winter barley yield level.