 If you liked
Suzumiya Haruhi no Yuuutsu (2009)
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 ...then you might like
Summertime Render
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A mildly reminder that this rec actually contain a very subtle obvious spoiler:
So whats make this two similar?
Summer
Time loop
Playing in the water
Supernatural event
Watch each, and you will get the vibe i mentioned above. Even if its not very well same in the grand concept of both series stories.