A lot of people are banking on the block reward halving for an increase in price.
That is more realistic than Christmas holidays.
Of course halving will have way more impact on bitcoin than the Christmas and I hope that the price of the bitcoin will grow significantly
"BTC will rise over Christmas" is an interesting variant on the "BTC will fall" theory that did the rounds last Christmas. Back then we had 2 Christmas rises (2011 and 2012) and 2 Christmas falls (2013 and 2014). Christmas 2015 saw a ~20% rise.
People sell BTC for fiat to buy Christmas presents, people use fiat to buy BTC to give as Christmas presents, and many people don't celebrate Christmas and continue about their daily routines, buying and selling BTC as usual. Historically Christmas provides no clear direction - price could go up, or it could go down.