The subtropical zones or subtropics are geographical and climate zones to the north and south of the tropics. Geographically part of the temperate zones of both hemispheres, they cover the middle latitudes from 23°26′10.1″ (or 23.43613°) to approximately 35° north and south. The horse latitudes lie within this range.

The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at 23°26′10.0″ (or 23.43612°) N and the Tropic of Capricorn in the Southern Hemisphere at 23°26′10.0″ (or 23.43612°) S. The tropics are also referred to as the tropical zone and the torrid zone.