“…According to the ACDP index calculated for Poland for 1951-2018, the largest area, i.e., >55%, covered by deficient precipitation in the spring season was determined for 1953,1959, 1963, 1964, 1974, 1976 and 1993. In the same years, precipitation below the multi-year mean was also recorded by other researchers in various regions of Poland, e.g., in March in 1963, 1964, 1974, 1976 and 1993 [8,49]; in April in 1974, 1976 and 1993 [49]; and in May in 1963, 1964 and 1974 [49]. Precipitation deficiency occurs with varying frequency, depending on the degree of its intensity and the region of occurrence, both of which are conditioned by climatic factors [50]. This study shows that deficient precipitation most frequently occurs in central-west and north Poland.…”