The aim of the investigation was to evaluate the amount and the frequencies of precipitation deficiencies and excesses during the growing season of late potato in the Opole voivodship in 1981–2010. It was also checked if the upward or downward trend of the level of precipitation excesses and deficiencies occurred during the observed period. On the basis of the research it was stated that the average sum of precipitation, during the vegetative season of late potato from May to September in 1981–2010 in the Opole voivodship, was approximately sufficient to fulfill the precipitation requirements of this plant. During the analyzed period, the observed weather conditions were good enough to secure the water requirements of the late potato, in almost every months except for August, which was dominated by the moderately dry and dry conditions (44 % of all cases). The moderately wet and wet weather conditions were mostly spotted in September (45 % of cases). The statistically significant upward trend α = 0.05 of the precipitation excesses occurred in Glubczyce region and the weak upward trend α = 0.1 was observed in Losiow. The weak upward deficiency trend of precipitation only in June in Losiow was noted. The medians of the monthly precipitation deficiencies ranged from 13 mm up to 43 mm, while the medians of the monthly excesses precipitation, during the whole period of the vegetative season of late potato, valued from 22 mm to 49 mm, however, they were less diversified than the medians of precipitation deficiencies. In the case of serious deficiencies in precipitation there was a significant fall of potato crop.