My recollection is that last month's winner wasn't announced until it was nearly time for this month's YDC. My suspicion, therefore, is that Rainy thinks that's when it's "supposed to happen" in so far as that phrase applies ot YDC at all. However, it seems to me that it actually used to be announced soon after the end of each run, and that it's better that way since it gives the winner time to think about their choice (and for us all to congratulate them).