Simulation of the increase in values and the frequency of precipitation deficiencies for cultivated crops have been carried out for the growing season (April– October). This simulation pertains to the Podkarpackie Province and takes into account following temperature increase scenarios: 1, 2 and 3oC. In this paper the agro-technical level was assumed for the end of the 20th century and sums and precipitation structure was assumed for the long-term period 1901–2000. The agricultural efficiency of precipitation was established using the multi-step regression analysis. This procedure was initiated in order to determine the dependency for dampness of the cover soil in reference to air temperature and precipitation. This study indicates that precipitation frequency during growing season along with precipitation deficiency will increase from 39% (during the period 1901– –2000) to 59, 76 and 92% respectively when we consider the above-mentioned temperature scenarios. There is a 5% probability of the increase of precipitation deficiencies during the period 1901–2000. Precipitation deficiencies will increase scenarios.