The sun is directly overhead at noon on the equinoxes at the equator, which is at 0 degrees latitude.

Here's why:

* Equinoxes: The equinoxes occur twice a year, around March 20th (vernal equinox) and September 22nd (autumnal equinox). During these times, the Earth's axis is tilted neither towards nor away from the sun.

* Direct Overhead: This means the sun's rays hit the Earth at a 90-degree angle, resulting in the sun being directly overhead.

* Equator: The equator is the imaginary line that circles the Earth at 0 degrees latitude, dividing it into the Northern and Southern Hemispheres. Since the Earth's axis is not tilted during the equinoxes, the sun's rays hit the equator directly.