Cold Days was Halloween. After that he stayed half a year on Demonreach. So, in Skin Game it would have been around May. In the first chapter of peace talks he told Thomas, that he was a full time dad for one month now. So, I would say, PT happens in June or July, depending on when he took Maggie to his new home.
In Christmas Eve the talk was about the events of "last summer" and "all the deaths" so there are several months between the peace talks and Christmas Eve. I don't think BG would be more than half a year after PT, but more like immediately afterwards.