Earth's solar year is 365.24219 days long. This is the time it takes for the Earth to complete one full orbit around the Sun.

Here's why it's not a clean 365 days:

* Earth's orbit is elliptical: It's not a perfect circle, so Earth moves faster when it's closer to the Sun and slower when it's farther away.

* Leap years: We add an extra day to February every four years to account for the extra quarter of a day in the solar year.

Let me know if you'd like to know more about the solar year!