The chart on the left above, called the analemma, combines the equation of time with the position of the Sun relative to the equator. Click it for a larger view, and notice that through most of the fall the Sun has been running ahead of the clock, but in December it began to slow dramatically.
It's the Sun slowing down relative to the clock that's moving the daylight period later into the day even as the days get shorter! (the latest sunrise of the year occurs during the first week of January)
This photo composite was made by Tom Matheson over the course of a year, snapping a picture of the Sun at exactly 8 AM (by the clock) each day. Here is a labeled image of Tom's photo.
(This blog is an edited re-post from December 2009)