November is the month with the highest frequency of summers in western Paran?.The climatic phenomenon ENOS has a more obvious effect on rainfall than the ODP in western Paran?.Rainfall variability in western Paran? directly affects soybean productivity.The distribution of rainfall during the phenological phases of the soybean crop is more relevant and has a greater impact on productivity than the total rainfall during the harvest.Water availability during the reproductive phases is a decisive factor in obtaining high yields from the soybean crop in western Paran?.