Abstract <p>We studied the effect of the cold season climatic parameters on the phenolic compounds (PC) amount in the leaves of three <i>Olea europaea</i> L. cultivars (Nikitskaya, Coreggiolo, Ascolyano) and subspecies <i>O. europaea</i> subsp<i>. cuspidata</i> (Wall. and G. Don) Cif. growing in dry subtropical conditions on the Southern coast of Crimea. Based on the data for the 8-year research period, it is shown that cold winters with stable temperatures below 5°C lead to a stable low amount of PC, while unstable weather with sharp changes in heat/cold stimulates their accumulation. Significant changes in the PC content in leaves of <i>O. europaea</i> genotypes during cold periods with sharp temperature fluctuations may be due to the activation of growth processes. It was revealed that the weakly frost-resistant subspecies <i>O. europaea</i> subsp<i>. cuspidata</i> is characterized by the highest PC amount, whereas the frost-resistant cultivar Nikitskaya has the lowest one. These data characterize high efficiency of the antioxidant system in Nikitskaya cultivar. The results of three-factor analysis of variance showed that the variability in the intensity of PC biosynthesis in the cold season depends more on the weather conditions of a particular year (67.5%) than on the genotype (2.6%). A reliable positive correlation between PC accumulation and the sum of precipitation, and a negative relationship with the duration of sunshine was established. Multiple regression equations were made in order to show the correlations between the amount of PC in leaves of <i>O. europaea</i> genotypes and environmental conditions in the cold season of the year: sunshine, precipitation and air temperature. The results obtained confirm the value of PC for the realization of protective mechanisms in <i>O.&#xa0;europaea,</i> against the unfavorable external conditions pressure during the cold period.</p>