The way Bostonians view the arrival of September 1 is best explained through a graphic by Leif Jones:
The most significant pivot on this date is the flipping of apartments. I can't verify this, but about 98.7% of all apartments in the Boston area rotate on September 1. In some ways it sounds like a massive collusion amongst owners, forcing the renters into a crowded market for higher prices. The competition is so fierce that you're forced to pay first, last, security, realtor's fee, and about anything else you can think of in one large payment minutes after deciding to live the next 12 (or 9) months in one space. I've lived in a number of apartments in the Boston area, and if you want to have fun with a real estate agent, show up on August 10 and talk about finding an apartment for September 1. I did this a few years in a row, and each time--with different agents--they broke out into a sweat and told me I was too late. Every time, I got an apartment.
Still, you'd be better off sleeping on someone's couch and grabbing something October 1, when prices ease up a bit and you're not milling around someone's living space at the same time as other prospective renters. If you don't, you're in a lifelong spiral around this date. Even if you're someone who's not moving because of anything academic, you're subject to this date because it's the starting point of a life of renting. The first year, you'll rent on September 1 for 12 months. So guess what? Next year when you're looking to switch apartments because you're sick of dealing with your roommate's? When it's time for a new apartment you leave when your lease has expired, again hinging on the same date as last year: September 1.