This may have been discussed elsewhere, but if so I couldn't find it. If you know of another thread that covers this please post the link. I find it hard to believe that I am the first to comment on this.

In Summer Knight, during the White Council meeting, Rashid privately talks to Harry and asks him about the Winter Emissary situation. At the end of the conversation this remark happens:

"What is the date?" the Gatekeeper asked.

"June eighteenth," I said.

"Ah. Of course." The Gatekeeper turned away, and sounds returned to normal. The Gatekeeper joined the rest of the Senior Council, and they trooped back up to their podiums. Podii. Podia. Whatever. Goddamned correspondence course.

It seems to be completely random. To my knowledge the date of any of the events in this book are never mentioned after this. When Rashid meets Harry in the woods after his visit with the Mothers he does not mention the date or the previous date at all. All I can come up with is that A: Rashid has been doing some time traveling and was confused about what day it was and was honestly asking Harry what the date was. Or B: Rashid was having Harry mention the date so that he would remember it because it will be important to him in the future (Harry did remember it up to the point when he wrote his case books whenever that was. I do not have an encyclopedic memory, but usually the books take place in a season not on specific listed dates (unless it is important like Halloween in DB or CD).

Any ideas as to which it may be or other suggestions on its importance. Once again feel free to direct me to another thread where this has already happened.