Here's my thinking on that, Laura: A hibernating tortoise is being kept in a very cool spot. When he wakes up, his body is used to the cool. If you bring him inside and warm him up, then you can't put him back out until it is really nice weather, but if you leave him where he is, its not harmful because he's acclimated to it. Just make sure he's dry. If its too cool for him, he'll just stay inside his house until it warms up a bit. No harm done. If he has food in his stomach, he'll come out and find some sun then go back inside. At least, that's what mine do.
Hi Laura,
Mine do as Yvonne's tortoises. An exception would be when they wake up too early.
Here from central CA south it is the right time. I don't know where you are.