Many programs let you rotate in July. Also, you can rotate all the way until November, although the latest I'd go is October.

There are many programs that take July rotators, but it can be tough because many programs give priority to their home students for the slots first. You might have a good shot at a community program that doesn't have home med students. It will give you an upper hand on your home rotation as well with 1 month of experience. It may work in your favor with a more competive program as well as they might not have as many applicants for that time (if not full with home rotators). Aug, Sept and Oct are the most competive months to get a spot for a Sub-I (Sept being most competitive).

FWIW - I did my first away rotation in June, which was nice because I was the only visiting student that month at a big name program and had lots of face time with attendings and residents. If your school is on an early schedule, it is not a bad idea.

I would have preferred to do my home rotation first, but I couldn't schedule it until later in the summer. This was my best alternative and it worked out. Some may tell you it is important to do your home rotation first as a warm up. It all works out in the end.