allshookup's reply is about the best you're going to get. Disney doesn't release official attendance figures, so anything that you might read will be tempered by individual perception during their particular vacation. And, you still need to factor in a lot of variables like national holidays, park events (marathon, gay days), on-site conventions, Disney room/ticket promotions, sporting events (Atlanta Braves spring training, annual PGA Tour event), cheerleading/dance competitions, Extra Magic Hour, and even the weather in terms of the number of Florida residents that might visit on a given day.
The best advise I could offer would be to search these forums (when the search function is working) for something like "January crowds". You'll likely get dozens of occasions where people have asked how the attendance was in January, and the replies that were left.
Good luck.