Question: When is the Sun directly overhead? (assume you are in the United States of America)
- Everyday at noon.
- On the summer solstice (June 21ish)
Answer: 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).
Here is a video I made over the course of a day in Louisiana. Note that it rains and then the clay softens the pen falls. At the end, my dog hit the camera even though I explained I was making a time lapse video. My dog never listens.