Final answer:
On the March equinox, around March 21st, the Sun is directly overhead at the equator, at the zenith at noon.
Step-by-step explanation:
During the March equinox, which occurs around March 21st, the Sun is directly overhead at the equator. This is when the Sun crosses the celestial equator, meaning it is located at the zenith (90° above the horizon) at noon to observers situated on the equator. The March equinox is a time when every place on Earth experiences approximately 12 hours of daylight and 12 hours of night, marking the beginning of spring in the northern hemisphere and fall in the southern hemisphere.