On 10th September 2013, Apple will announce to the world the next iPhone to replace the 5, likely to be called the 5S and also the iPhone 5C (colours). In addition, a new full size iPad will be available that will be considerably lighter and have a smaller profile too. The iPad Mini is likely to feature a retina screen.
In addition, it has been a whole year without a new product from Apple. So Apple fans will be dying to reach out for the next big thing. Next iOS 6 will be replaced by iOS 7 and again this will help fuel the sales. And who knows, maybe the next new thing will appear from Apple as well.
Then there will be the marginally improvements to the rest of its range, maybe at lower price points too.
All in all, with all the changes and new markets to sell too, Apple is aiming for one mammoth sales campaign this fall.