Cartographically speaking, the subtropics include all parts of the world just outside 23.5° north and 23.5° south latitude, the limits beyond which the sun never appears directly overhead at any time of the year. However, because of terrain, winds, and ocean currents, subtropical climatic types may stray outside these geographical limits, or may not quite reach them.
Under the Köppen-Tregartha system, there are three basic types of climate found in the subtropics. B climates are steppes and deserts and C represents humid subtropical climates, including marine west coast and Mediterranean climates. H is a catchall for high, rugged mountains that contain localized microclimates too varied and scattered to categorize.
By Dave Bryant, copyright 2002