In my experience end of the year (approx mid December) is typical to have a significant dump of coins due to traders locking in profits before the end of the year, people going on holiday and needing money, etc.
Yes this is more likely happen during December, I`m a holder, but somewhat I failed to hold some tokens and it keeps dragging me down until now why I didn't sell in December. It's a big mistake for me, not to ask somebody, well anyway being a novice in trading and holding always experience something like this.
End of the year is where big holidays are happening. So people tend to transact more and a lot money movement around that time. Its normal that market is expected to go up due to people will use their coins at the time.