My first orchid was a Cym given to me by a co-worker who lived inland - fairly frequent days of triple-digit F temps (38-40 C or more) in summer (She grew them under a big deciduous tree... shade in summer, lots of light in winter when leaves dropped, frequent winter night temps near freezing). To show how cold-tolerant they are, I a refer people to this:
Ice - Freeze of 2007 . I saw the plant with the big sunset-color flowers shown on the site, 2 weeks later in a show... not only did it survive the cold, it was still show-quality. No damage at all to the flowers. Cyms are fine down to about 29 deg F (-2 C) Below that you may lose some buds and flowers, but the plants can take a few more degrees of frost especially if they can warm up a bit during the day.