It was late August when I was going to school there--maybe mid by the time I was finishing. I know the schedules are different now with fall breaks being more common, but July 29 sounds insane to me. Also, the district these kids are in (and that I went through) is on a four day school week now because of budgetary issues. This is either the first or second year of no Friday classes there.
When I was a kid, it was usually after Labor Day in grade school, and late August for high school.
My brother started teaching last Thursday, but had to start working about a week before that with meetings, etc. The kids do get a 2 week break in October and again in Late December, and again 1 week at Spring Break. I guess the day count is not much different throughout the school year (compared to starting mid August), but damn, it's AZ, man! Who wants to go to school in late July when its 110+ out?
My brother chalks it all up to the parents in his district wanting the dates moved up because it's free day care, as far as they are concerned.