I'm with NoHall on this one. I think the schools vary by area within each state, and public schools may vary from gov't schools, in the same area.
Texas Spring Breaks will be all over the place, as well.
Curiosity killed the synchronicity. The first 5 counties (metro Atlanta) I looked up had the dates I already gave. But some of the north Georgia counties popped up with different dates. I'm stopping short of looking up all 159 counties, but suffice it to say that if the state has decided to synchronize, it is not yet in effect.