My sulcata is 16" long and 21lbs. What is the minimum temperature he can be outside? I live in Edmonton, Alberta, Canada, so most of the year it is too cold.
Use a temp gun and measure the ground in a sunny spot where you want to put him. Then measure your tortoise's carapace every so often while he's out. If its sunny without a lot of wind, I'm comfortable putting a larger one out at 65 degrees. For hatchlings, I like it warmer 70-75 and climbing.