What is solar noon?
Solar noon explained: when the sun is highest, why it is rarely at 12:00, and how longitude and the equation of time move it.
The sun's highest point
Solar noon is the moment the sun crosses your meridian and reaches its highest point in the sky for the day. Sunrise and sunset are symmetric around it, so it sits exactly halfway between them.
Why it is rarely 12:00
Clock time is set by your time zone, which usually covers many degrees of longitude. Unless you happen to sit on the line that defines your zone, the sun reaches its peak before or after 12:00. Each degree of longitude away from that line shifts solar noon by four minutes.
The equation of time
The earth's tilt and its elliptical orbit mean the sun runs a little fast or slow against clock time through the year. This difference, the equation of time, swings between roughly 14 minutes slow in February and 16 minutes fast in November, and it nudges solar noon along with sunrise and sunset.