Most people have at least some extra free time during the summer. Some of that time should of course be used for recharging the batteries, but try to keep learning Chinese even if you're no longer enrolled in a course.
This article will suggest a few things you can do to learn Chinese during the summer vacation.
Cultivate your interest
Focus your learning on things you really enjoy. They don't need to be directly related to languages, so watching films in Chinese with English subtitles is fine, it's much better than not watching the film at all. If you're not into film, focus on whatever you find interesting but usually don't have time to do. The important thing is that it's fun and that it's related to Chinese. Only study related material if you feel up to it.
Review what you learned
Chinese isn't like other subjects where you can study one area and then leave it. When studying languages, every step builds on the previous steps, so going back and strengthening the foundations is a good idea. Do you really know the stuff you learnt during the spring?
There were certainly some bits you skipped because you didn't have time or no-one to ask at that time. You might also have taken notes about related areas you'd like to explore. The summer vacation is a great opportunity to do this!
Preview what you will learn
Previewing is underrated, especially in language learning. Many students don't think it's necessary to prepare much for class since the teacher will explain most things anyway, but if you have previewed properly, you'll be able to make much more of the teacher's explanations and you will also be able to ask the right questions. Of course, in more intensive programs, students are required to have previewed chapters ahead of time and the teacher won't go through the basics, but this is still an exception. Looking at what you're going to do in class next semester is a good idea, but don't overdo it.
Broaden you knowledge
Many courses and textbooks have the common flaw that they get to more advanced material too quickly. They only show you one path through a number of topics, such as sports, food or entertainment. In the sports chapter, they might focus on basketball, but there are many other sports that might be equally. The best way to broaden your knowledge at a beginner level is to get more than one textbook or get a graded reader. More advanced students should try to read and listen more, but choose material which isn't too hard.
Travel to China
This requires a lot more effort, but can also be exciting, getting away from home for a few weeks and experience a different country and culture. If you feel up to it, you can of course focus on language while you're in China, but just travelling around will be great if you've spent a lot of time in the classroom.