User blog comment:Blue Luna/Timeline guide/@comment-5522921-20160926035457/@comment-25047329-20160926041804

Admittedly, this part confused me a lot too and may not be accurate. Looking through the whole first manga and then some to get this info, I realized that Ishida's sense of time can be rather iffy, if not outright inaccurate. When I first read the Rize oneshot, I also assumed that it was six months before the SBI. However, Rize has a calendar in her room that says it's December. This also seems to correspond with the environment as everyone is dressed warmly and some of the trees are dead.

I now think that the six month difference might be referring to Kaneki and Rize's first "meeting" rather than their date. The chapter ends with them seeing each other as Rize leaves Anteiku. The thing that throws me off is that Kaneki is dressed in this big ass coat implying that it's cold. It's kind of big even for October though imo (but idk how cold it gets in Tokyo).

Idk if this is something that can be further cleared up and it's iffy either because of mistranslation or a misunderstanding on my part, or if it's Ishida miscalculating something.