I have a friend that I see through five months of the year, but when I look back, he is gone. What is his name?

This is something I thought up earlier today.

I'm not sure if the phrasing is too ambiguous or not. I've been doing cryptic crosswords lately, which include very misleading clues (hint hint).

Give me your answers and any suggestions on phrasing that might make this better, without making it too easy!