It is all, but certain that Apple will announce the next iPhone on September 10th. The new iPads though, are another question entirely, and if the latest rumors are to be believed, then Apple will follow the game plan they used last year. In 2012, Apple held the iPhone 5 event on September 12th, and the iPad mini event on October 23rd. In 2013, Apple is set to hold the iPhone 5S event on September 10th, and it appears that an iPad 5/iPad mini 2 event will be happening around October. According to Bloomberg, Apple is set to release the iPad 5 and iPad mini 2 in the final three months of the year.
The phrasing “last three months of the year” clarifies that new iPads will not be at the September 10th iPhone event. It also makes October most likely, because Apple wants to release new iPads in time to get the most sales from the holiday shopping season. The report goes on to claim what we are already expecting, in that the iPad 5 will have a thinner design, and the iPad mini 2 will offer a retina display. The iPad 5 will have an iPad mini like design with thinner side bezels, and reductions in weight thanks to using the same film based touch panel sensors of the iPad mini.
New iPads are coming, but they will be coming later in the fall than the new iPhones.