Q.Can a Christmas Cactus live outside in the summer
We live in a semi arid climate (middle of Wash. state). Gets hot during days and cooler at night.

Christmas cactus will prosper at temperatures hovering between 60-70 degrees and will, according to my research, tolerate temps in the 90-100 range - if you are really looking to push the envelope. You can put a christmas cactus outdoors, but not in the sun otherwise you run the risk of burning the leaves or the leaves going limp. Keep it in a shady or semi-shady location.
For more information on the care of christmas cactus, please visit the following link:
https://www.gardeningknowhow.com/ornamental/cacti-succulents/christmas-cactus/advice-for-christmas-cactus-care.htm