It seemed to me that the hunt was something that Yharnam dealt with all the time since they started. A lot of items read that they had a sickness or disease they couldn't figure out (Probably why there's so many goddamn coffins and headstones all over the goddamn place) that made them become beasts. This one seemed different, I think, because the Great Ones were heavily involved.
What it seemed to me was Bergenwerth, the Church and the Choir all found out about the Great Ones and in an attempt to contact them and use them to escape this disease. They began to obsessively try to communicate and emulate them that they instead of succumbing to the Beast they went the other way around and became something else entirely inhuman. Thus this night became about both Beasts and about the Great Ones.
The day and night Cycle seems not to be different, I think it's different this hunt because of the Great Ones and their affinity for the Moon.