Here's When Apple Will Likely Start Selling The Next iPhone

It's all but confirmed that Apple will formally introduce its next iPhone, which some are calling the iPhone 5S, at an event on September 10.

But when will it actually go on sale?

Assuming Apple follows its product launch pattern, the answer is September 20.

How did we arrive at that date? Let's break it down:

Historically, Apple has launched new products on Fridays. However, it also likes to make sure reviews for the new product are published before the launch.

So, here's what will probably happen. As it always does, Apple will give a select group of tech journalists the new iPhone to review following its announcement on September 10. These journalists must agree not to write about the device until a certain date and time. That embargo has traditionally lifted on a Tuesday at 9 p.m. Eastern when AllThingsD's Walt Mossberg, who is very close to Apple and is the most influential technology reviewer in the world, publishes his weekly column.

September 10 is a Tuesday, so Mossberg and Apple's other cherry-picked tech writers will likely have to hold off on publishing their reviews of the new iPhone until Tuesday September 17. Apple will then likely start selling the device on Friday September 20, keeping with its Friday gadget launch tradition.