One thing I've noticed or maybe possibly imagined, it seems to me that when your in Diagon Alley in the evening the place feels significantly cooler than the rest of the park. The height of the walls seems to block most areas from direct sunlight. The air-conditioning also seems to flow out of the shops and Knocturne Alley and really has nowhere to go and seems to linger in the area. Maybe it was the particular times I visited but something I noticed, in any case a very nice unintended benefit of the area.