What temperatures are best for a Crown of Thorns kept outside?
What Are the High and Low Temperatures for an Outside Crown of Thorns
Certified GKH Gardening Expert
As long as it is kept above 25 degrees, it will be ok. It can only withstand these temps for a very short period. It, really, needs to be kept above 50 degrees to be happy. This collection of articles will help: https://www.gardeningknowhow.com/houseplants/crown-of-thorns/