Apparently there is an unwritten rule in search that Google doesn’t release an update during the holiday periods. This is so that those that are away over the holiday periods aren’t effected by any changes in the search world that could have consequences on their search presence.
@Bessian Actually, we try to minimize major updates right before the holidays.
— Matt Cutts (@mattcutts) December 18, 2013
A tweet from Matt Cutts during 2013 (see below) stats that they try and minimise updates before the holidays and like most things Matt Cutts says people jump on it and take it as law.
I personally think it’s irrelevant whether or not they update anything apart from Christmas day I personally have nothing better to do. However thanksgiving this year Google released a huge Penguine update and it has ticked a few people off in America.
Google for some reason has denied the they intentionally released an update before thanks giving, and that the current updates are part of a six week schedule of updates as part of Penguin 3.0.
Off topic a little – Do Google name their updates to mock us? Imagine talking about penguins and pandas in meetings, people outside the conversation must think we’re very weird.