A type of climate characterized by continuous high temperatures in combination with abundant rainfall (in excess of evapotranspiration) throughout the year. This climate is the type required to support the growth of the plant group known as megatherms. This is an (A) climate under the Köppen classification (1931) and, as defined by Thornthwaite's climatic classification scheme (1948), this is a climate with annual potential evapotranspiration in excess of 114 cm. Compare mesothermal climate, microthermal climate.