How cold? If "overnight Alaska" cold, that is way to high to start with. Dave M is right - should start at more like 20 psi. If overnight in a 80F degree heated garage, it's probably OK. That can really only be a bad regulator, only way to tell for sure is swap it. Too bad, because it appears to have the right pressure as soon as it warms up. Strange failure mode. More typical of a bad regulator is a 70psi reading all the time.