Never been to Waverly Hills myself but cold spots at old sanatoriums like that are genuinely fascinating from a research angle. The thing I always want to know is whether anyone bothered to check for draughts or ventilation shafts nearby, because a lot of "cold spots" have a perfectly boring explanation once you start looking.
That said, I've been in places in Liverpool where the temperature drop felt completely different to a draught - more like stepping into a pocket of air that just shouldn't be there. Hard to describe unless you've felt it.
Did it feel sudden? Like crossing a threshold? Or more gradual? That distinction matters quite a bit when you're trying to rule out the mundane stuff. Would love to hear from others who were actually there because Waverly Hills is on my list and I want to know what I'm walking into.