OK, GLC, I now know where you went to HS ... right down the road. I moved back here in 1990 and they were still subscribing to that theory. It ended just a couple of years ago, when there was a new superintendent or some other change like that. Plus, there were a couple of storms where the district got some very bad press for putting the kids and teachers in harm's way, trying to get to school in a blizzard.
Personally, I liked the February and April vacations for the same reasons you did, except that airlines leaving from Boston still jacked up the prices, even though it was generally much cheaper to stay in hotels, etc. during those times. We went back to AZ to visit a couple of times in February, and it was nice. I hate traveling in December, unless it's by car. I must say, though, since I left teaching, it's been really nice to take a x country ski trip in January, when no one is around!