Opinions will vary. But here's what I would do: I find a snake on a cold day. I hold on to the animal until the next warm spell (say 60 F degrees) which hopefully it isn't too far` off. Provided the snake has good body weight and looks healthy, I would release it where I found it. Naturally, many factors could play into as to why the snake was found stranded on a cold day. It could be injured for all I know. If the cold persists, well then I have a pet snake until spring. Good luck.