subtropical humid subtropical ORCID:0000-0002-4366-3088 A humid subtropical condition is a subtropical condition in which an environmental system has hot, humid summers, warm to cool dry winters, and average annual precipitation either evenly distributed throughout the year or marked by a dry season or drying trend during winter In cases where rainfall is evenly distributed throughout the year, this condition falls into the Cfa category of the Köppen climate classification. In cases marked by a dry season or drying trend during winter, this condition falls into the Cwa category of the Köppen climate classification. Environmental systems with this condition usually occur on the eastern side of continents.