It is one of those holidays JWs do NOT celebrate. There is no reason for it. It is not a religious holiday. It is not a political holiday. In fact, there is absolutely nothing in the WT Library that says JWs can't celebrate it, at least not in the last 50 years. Yes, in 1956, there was one single article dealing with this, and it's full of nonsense. Basically, WT says it's creature worship.
For the full 1956 Awake! bound volume:
http://ia600304.us.archive.org/27/items/WatchtowerLibrary/magazines/g/g1956_E.pdf
Or, the applicable pages: