A FlyerTalk Posting Legend
Join Date: Sep 2009
Location: Minneapolis: DL DM charter 2.3MM
Programs: A3*Gold, SPG Plat, HyattDiamond, MarriottPP, LHW exAccess, ICI, Raffles Amb, NW PE MM, TWA Gold MM
Posts: 100,413
For December 31st, it might matter exactly when (dates, not time of day) you check in and check out. There also could be a difference in the answer for nights credit versus stay credit, so be sure to phrase your question carefully and provide all details.