The sun is at its highest point at solar noon, and the exact time of that occurrence changes each day. Solar noon does not necessarily occur at earth's noon each day, according to the U.S. Environmental Protection Agency.
Information about a location's latitude, longitude and time zone are necessary to calculate solar noon. The axis and orbit of the Earth all account for the difference between clock noon and solar noon. Clock noon occurs after solar noon in the beginning of December, and the two times get closer together as the calendar approaches the winter solstice on December 21. Clock noon occurs before solar noon by the end of January.