Yeah, Dec 31st is Wednesday in 2014.
And it is already Wednesday, 2014 (but Jan 1) accross the dateline in places like Australia.
The logic to figure out the day of the week must be 'goofy'. Maybe some sort of universal time translation bug going between date and day.
By the way, I had run into a 'bug' 14 years ago, when trying to one-click record the year 2000 new years eve fireworks show on my Tivo. It tried to go back and record the bit of 'buffer' from the previous year and ended up crashing and rebooting the unit instead of recording the show.