While the manga version of Kimi no Iru Machi is unlike 5cm Per Second, the anime version is. Both construct a romance that is present despite a large separation between the two protagonists. The story-telling is also similar between the two; both anime titles tell their respective stories out of order. While Kimi no Iru Machi is a bit more light hearted than 5 cm Per Second, it has the same dark underlying tone. Finally, the music of Kimi no Iru Machi and 5cm Per Second both involve a beautiful piano piece that creates a very enriching atmosphere for the respective series.
These are two short anime that show the difficulties of maintaining a long-distance relationship. Male and female leads inevitably become distant to each other because of the distance in their living quarters. Both have a bitter-sweet feel.
Although the concept is a little different. The idea of romance is quite similar.
Both involve the guy being, what you would call "shy".
Furthermore, both have the sense of romance triangles flushing through flashback memories.
Main protagonist and girl both have feelings for each other. However, it's not that simple. There are countless misunderstandings and obstacles in the way. Like drama? like love triangles? like romance? Then, you might be interested in both series.
Some scenes, especially the station scenes and the snowy background reminded me of Bokura ga Ita. As well as the similarities like High school students, separation, long distance relationship, ex-lovers, admirers, problematic family matters... You can find them in both. But Bokura ga Ita is far better.