If what this manga talks about hits close to home, it's an instant top 5.
The story doesn't bother to hide its intentions. If you've read a certain quantity of manga, the ending is very predictable, but this plays out in favor of the story and is very intentional. Since the conclusion is clear, you gradually develop a growing sense of anxiety and dread, which increases proportionally to how attached you grow to the cast. This, in fact, is how what happens throughout the narration is lived.
Another intentional aspect is the duration. It's very short, which, if you've had the misfortune of living through what the story talks about, you know is just how it happens. This enhances everything that it talks about to the maximum.
The duration also affects how characters experience growth. As mentioned at the start, if the story's themes are familiar, The Summer You Were There will hit very close to home. However, if they are not, this might be the only hindrance you'll encounter. Since it's only 32 chapters, the character development is quite limited, and much of it relies on the reader having personally (or very closely) lived through what the characters are living through. Not to say that they're flat, far from it. But I imagine it would be hard to understand each of their motivations with such little time with them without having lived it first-hand.
This story is very special and has one of the best endings I've had the pleasure to read. Do not be dissuaded by the "yuri" tag: it feels so natural that you never think about it.
Give it a try; you won't regret it.