All is quiet in the year indication aperture from January to November - the dot of color seems not to change, even though it clicks ahead once each month. But in December, we are prepared for the coming change of year - a "split screen" appears, with the current year's color on the right, and the upcoming year's on the left. This year we see black moving to follow yellow:

Last December, we saw yellow moving to follow red.

Not sure why GO chose to do it this way - it would also make sense for the color appear to change over along with the other indications in the apertures. It is really just a function of how the underlying wheel is aligned with the aperture. Perhaps the folks at GO wisely figured that wearer is likely to be out having a wonderful time on New Years Eve, and didn't want to distract him (or her) with a complete color change at midnight
