Went over this before, but it's worth repeating. The Cfs2, as all other seasonal modeling, has December as a dumpster fire, which all have acknowledged. The question is what about January and February, as the Dec-Feb average is and has been skewed by December's warmth. This can be seen on the monthly temps link below. I am going verbatim just as your post, and clearly January and February are not as bad is December, and never have been for that matter for the last month. Whether the Cfs2 and other modeling is accurate is whole different discussion.
https://www.cpc.ncep.noaa.gov/products/CFSv2/htmls/usT2me3Mon.html