In the movie "Your Name" (Kimi no Na wa), we see Mitsuha waking up in Taki's body, but we later realise that she has been dead for three years. This means that she was waking up in future‑Taki's body, so Taki lives three years into her future.
So, how does she not realise that she is seeing into the future? The dates must be everywhere: she checks and logs stuff in his phone, surely she must have seen this.
And, if she has realised that she is seeing into the future, why doesn't she bother finding out about her town or anything? Because it's the future, surely she would want to know how Itomori looks three years into the future.