The holidays are a very busy time for everyone, both professionally and personally. Your colleagues are probably bogged down with out-of-town guests, gatherings with friends, a shopping list that's pages long, and so on and so forth. Not to mention that they have to get all of their end-of-the-year work projects complete before they can truly relax.
Because the holidays can be so busy and stressful, why not consider having your company's party after things have calmed down? Book a venue sometime in mid- to late January during the off season can save you a lot of money. It may even be a relief to those attendees who would have otherwise declined the invite due to a packed schedule.