Clocks Go Clockwise Because of Sundials

The familiar direction of a clock’s hands is a tradition inherited directly from the sun. Long before gears and springs, humanity’s primary timekeeping device was the sundial. In the Northern Hemisphere, where the first mechanical clocks were developed, the sun appears to travel across the sky from east to west by way of the south. As a result, the shadow cast by a sundial’s central gnomon sweeps in a rightward arc, moving from morning on the left to afternoon on the right. When 14th-century European inventors designed the first clock faces, they simply mimicked this natural and universally understood motion.

This clockwise standard, however, is purely a quirk of geographical history. If you were to set up a sundial in the Southern Hemisphere, in a place like Australia or Chile, you would witness the opposite effect. There, the sun's path arcs through the northern part of the sky, causing the sundial's shadow to move in a leftward, or counterclockwise, direction. Had the technological centers of the world been located south of the equator during the advent of clockmaking, our walls and wrists would almost certainly feature clocks that run "backwards" by today's standards.