Do reviews happen more in Holiday season? When I recently inquired about the status of my paper which is currently in the "under review" status, the editorial assistant informed me that they are still awaiting referee reports, and the Editor is expecting that the review process will be completed at the end of the January. Its been a year I have submitted, and I am a bit startled that the editor has given a specific time of completion, rather than just say that it's still pending. Could there be any specific reason? Do reviews happen more in the holiday season generally? Assuming the reviewers have ample leisure time to study the paper? Does this indicate anything about the incoming decision?
Reviewers set their own schedule subject, more or less, to deadlines set by the editor. Some might use holidays to work on reviews. Others might rather avoid anything that looks like work. The "end of January" may be a guess or may be more firm, depending on the deadline request sent to reviewers. Perhaps a reviewer has made a "promise" to be done by then. 

And what is "expected" may not come to pass since reviewers aren't employees, but volunteers.