A forecast about the frequency of occurrence in southeastern Poland of the pluvio-thermal conditions that are unfavourable for principal cultivated plants was prepared for three scenarios of temperature increase (by 1.0, 1.5 or 2.0 ºC) over the long-term period average of 1901–2000. The simulation was carried out using Selianinov’s hydro-thermal coefficient whose values were calculated for each month in the growing season (April– –October) assuming steady precipitation and appropriately increased air temperatures. The critical values of Selianinov’s coefficient were established on the basis of how the state of cultivated plants in the field responded to the changing pluvio-thermal conditions. For the scenario with 2.0 ºC temperature rise, it can be expected that the frequency of deficient humidity conditions would increase from 23 to 33%, and that of excessive humidity conditions would decrease from 23 to 14%.

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