So my wife was rewatching Frosty the Snowman (it's going to be a long holiday season...) and the kids are in school on Christmas Eve.
The show aired in the late 60s. Was it common for there to be school on Christmas Eve in the US at the time?
In 1954 and 1965, for example, Christmas fell on a Saturday. School districts that allowed the customary two weeks could stick to a strict Saturday to Sunday period, with school held on Friday, off two weeks, and then resuming on Monday, so in years when Christmas fell on a Saturday, it was be possible for school to be held on Friday, the day before Christmas. This was the way the Washoe County School District in Northern Nevada handled things in that decade, and I suspect it was not unique.