It's super cold out, bring him in tonight, keep him in a bathroom or other confined place and then think about it in the morning. I'd say don't take him to ACCT, they mean well but are always too full. Find a no kill shelter to take him. Also look on PawBoost for lost cats. And while I am not a cat person, and "say" I would never take one in, you may have been chosen - meaning you're now married to said cat.