First of all, nobody knows except Apple. All of the pundits are guessing. Even if you are working on the assembly line putting the phone together, you have no real way of knowing when it will launch.
Prediction #1: iPhone 6
Yes, there will be a new iPhone this fall and it may be called the iPhone 6, it may be called the iPhone Air, or it could just be the new iPhone.
Screen size: There is speculation that it will have a bigger screen or that there will be 2 different sizes of screen and my guess is that we will not see the larger screen this year. I think that when Apple extended the screen the last time that the change was made for the next 3 - 4 years which means we probably have 2 more years of this form factor. Part of the reason is that people get really upset having to buy new sizes of accessories. Seems silly but it's that kind of thing that ends up annoying people.
Prediction #2: iWatch
I am going to go out on a limb and say that there will not be an iWatch introduced this year meaning 2014. The wearables market is already seeing gear from competitors like Samsung, LG, and the much anticipated Moto360. The reviews on these devices basically say "Nice but not great" which tells me that it would be a bad move to introduce a new iWatch because the market is already wondering if these are necessary and launching it so soon after others makes Apple look a bit desperate.
Most people assume whatever Apple introduces will be incredible and with the other watches only working with Android, Apple isn't really losing current customers unless those customers switch from iPhone to another phone. That could happen but the numbers won't be significant since people would have to break their contracts and do massive data migration.
The only reason I could see to introduce the iWatch in the fall would be if it will have the health / fitness tracker capabilities. Everybody will want one in January as they fight off the holiday pounds and look to get in shape for spring.
Prediction #3: Macbooks in multiple colors
The Macbook lineup have been excellent over the last few years but with a lot of great Apple products, they look a bit boring after a while. This fall would be a great time to introduce color to the Macbook line.
People were willing to pay $200 extra in the past for the black polycarbonate Macbooks and I think that being able to get them in multiple colors would spring a little life into the sales of the product line. Not that Apple needs to sell more as they do well enough but when the competition is cheaper and getting thinner, it would be nice to be able to buy a black Macbook Air to show off some style.
Prediction #4: CarPlay
With CarPlay launching this summer / fall, there is going to be a lot of visibility on Apple from the support perspective for the in car experience. While it's not a requirement that it launches without any issues, having any problems that become news will be a black eye on their launch into this marketplace.
The aftermarket systems from Pioneer and Alpine are going to do very well. There are a lot of people out there who don't want to use a GPS, an iPod, a Stereo, and CD Player in their car when their phone can do it all. CarPlay will be a hit because it gives people exactly what they have always wanted