3F outside according to one of my wireless thermometers. I could not use 2 in the greenhouse to monitor 2 levels under the frost cloth because they were picking up each others signal. So only one under the cloth is sitting in a pot about 1 foot off the floor, and its reading 40F. The single wall greenhouse itself is 18F. I think it passed, I can at least put lots of smaller potted plants in the greenhouse (non tuber forming elephant ears, Basjoo pups, etc.) in winter without a stove.
