early- all of my vanda's and other assorted "hangers" are outside here all winter in the shadehouse. You can't do that in NM.
That being said, we do get a handful of nights over the winter where it gets down into the mid 50's and we had one night last year it went all the way to 48!!!!!!!! They were all just fine because the next morning the sun comes out and it will be up to 70 by 10:00.
As rbarata said though, if you grow inside, I would try and hold the bottom at 65. Continuous exposure to much below that will likely at least stunt their growth. Do the best you can to keep that humidity as high as you can. With vandas's that's almost more important than the temp.
Glad to hear your Zygo is hanging in there. Those all get spots on their leaves so try not to look at that.
