I do not grow those types of orchids..but in my area where we are now getting fluctuating low mid 40's to high 50's overnight, I have moved some of my orchids indoors and only the ones that are more temperate still in my growcamp outdoors. I have been using the plastic foil covers now, to at least ward off some excessive chill at night.
There is just a limit to what some of the orchids can take, on the side of caution, I will do what Ursula says..find a warm spot indoors now, so the transition will not be too drastic for your orchid. My thinking is you may lose the bloom, but at least save the plant itself from cold damage.
