On March 21st, the sub-solar point is located at which latitude?

The sub-solar point is the location on Earth where the sun is directly overhead at solar noon. This phenomenon occurs at the equator, which is at 0 degrees latitude. On March 21st, which is around the time of the vernal equinox in the Northern Hemisphere, the sun shines directly on the equator. On this day, both hemispheres experience nearly equal amounts of daylight and darkness since the sun crosses the celestial equator.

Understanding this concept is fundamental in physical geography, particularly when studying solar angles, day length variations, and seasonal changes. The significance of the equinoxes—March 21st (vernal equinox) and September 23rd (autumnal equinox)—lies in their consistent occurrence at the equator, where the sun's rays are perpendicular to the Earth's surface. This further establishes 0 degrees latitude as the correct position of the sub-solar point during that time.