I believe one of the themes of this movie could’ve been the thought of a timeless love. There did not have to be an exact point in which the relationship began- was it the honking of the horn, seeing him playing the piano at the nightclub, the dance, there is no exact point in which their declare their relationships beginning.

In this degree I believe there is no timeframe of the movie itself, the costuming and sets could be of any decade particularly the 50's, some 70's, etc. however the use of technology and some of the surrounding ideas bring the time into our own current time.

We again have the idea of a timeless love with the expression of seasons, not dates or years (to my recollection). Expressing not necessarily a timeframe, but an emotion or feeling from each season and what to expect with its presence.

Finally the idea of the timeless love between M&S is confirmed with the traveling of a time or a different time that could’ve been. The life they could’ve shared in a different time and space. This leaves us with the closing idea that perhaps their relationship may have ended but the love never did. The love is timeless and has created the worlds they both so desired even if they did not achieve these desires in a place of a relationship, they were achieved through their love, a love which had no beginning or end.