Why does school start so early in Las Vegas?

I originally hail from the Midwest and back East, where school traditionally started each year after Labor Day and final examinations took place no later than the following June. So I find that the Clark County School District’s insistence on starting the school year during what is still the peak summer heat of our desert climate to be extremely puzzling.

Purely from a financial perspective, it would certainly make sense to save money by reducing the substantial air conditioning costs needed during the month of August.

Despite the incessant wailing about being inadequately funded, the district apparently has money to burn (or perhaps to cool) in this regard. There’s absolutely no need for any energy conservation whatsoever. Am I missing something?