Abstract <p>The changes in weather conditions from May to August were analyzed to determine their effects on the spring barley crop yield within the stationary experimental design. The investigations were carried out on the dark grey forest soil in Sverdlovsk oblast in 2002–2024. The two-factor experimental design involved the crop rotation cycle (factor A) with the variants including grain-bare-fallow-grass, green-manure with rapeseed-no-perennial, grain-grass with 40% legumes, grain-grass with 20% legume perennials, and grain-grass with 40% perennial legumes and the nutrition background (factor B), including the zero-fertilizer, mineral (N₃₀P₃₀K₃₆), and organo-mineral (N₂₄P₂₄K₃₀-manure-green-manure-straw) variants. In May and August from 2016 to 2024, a total decrease in precipitation by 35–40% was recorded compared to the normal. In June and July for 2002–2024, precipitation was at the level of the long-term parameter values. In the period from sowing to full ripening of barley grain, a 0.8–1.7°C increase in the air temperature in certain months of vegetation was observed compared to the average long-term parameter values. A decrease in precipitation in August and an increase in the temperature in the second half of summer contributed to reducing the period of barley grain filling and ripening. Considering the divergent pattern of the agrometeorological factors over the research years, the hydrothermal coefficient for most crop rotations comprised 1.33–1.43, with the exception for 2021–2024 (0.93). The barley yield for the control variant was, on average, 2.36 t/ha; the use of N₃₀, P₃₀, and K₃₀ contributed to the increase of 1.38–1.47 t/ha. A reliable positive correlation between the barley yield and the hydrothermal coefficient in the period from germination to tube formation was revealed. After the barley heading-phase onset, the influence of hydrothermal factors on the grain-crop yield performance was found to be weaker.</p>