Unfortunately, cold weather will not kill the scale. You need to try spraying with an insecticidal soap. Or depending upon the degree of infestation, maybe even a systemic insecticide, which is always a drastic measure on any plant. So try the insecticidal soap first. You can get it in Lowe's or Home Depot. And keep your orchids on the other side of the room. They should be alright there. Good luck...
