Over at The Grade, Steve Giegerich blogs about districts that are holding a professional development day today. He fears this scheduling decision could irk parents who have to arrange child care for the extra day.
To me, it sounds like a pretty good idea. If a professional development day falls in the middle of a regular school week, the entire week is disrupted. Teachers have to spend extra time reviewing what they covered before the day off, and it takes away from the grading and lesson planning they might normally do on that day to prepare for the rest of the week. Scheduling professional development on the first day after a break solves the problem.
As for the child-care dilemma, parents already knew winter break was coming, and they had to plan accordingly. I imagine adding an extra day to the break would actually be easier on parents than choosing some random day in the spring semester (which would require them to make those plans all over again).