Question

The mid-day sun is exactly overhead in between ______ and _______once a year.​

Answer 1

Answer:

Everyday at noon.

On the summer solstice (June 21ish)

For continental U.S. the answer is never. Since the Earth's rotation axis is tilted 23.5 degrees with respect to its orbital motion around the Sun, one would have to be less than 23.5 degrees above or below the equator to have the Sun pass directly overhead (once per year).