MI should be a fine place to grow orchids. My daughter just moved out there last fall with her houseplants and orchids. She was fortunate to find a house to buy this spring with two enclosed porches, plenty of windows and light. Her humidity seems to be great, but she's fairly near the lake too.

I suspect that when its really nasty out, you'd want to move the plants away from the window a bit to protect them from cold. I'm assuming your windows don't keep the cold out very well. You sure had a terrible and cold winter last winter! You could also put plastic over the windows to cut down on drafts. Better for them to miss out on some light and live than to get frozen and die, poor things. I agree, get a thermometer to put in the orchid area to monitor conditions.

I know a sudden cold night knocked the flowers off one of my blooming catts this spring. I took them all out to my (enclosed and heated) grooming shop to do some potting and spraying and forgot to bring them in and forgot to put the heat on. I lost a few leaves on a couple of plants and the flowers off the catt. It wasn't that cold, but they weren't used to it either.