I'm with Dutch on this. Cooler temperatures aren't usually a bad thing, it's the humidity that you want to watch out for. If the temps drop too low it'll probably take longer for the buds to dry and cure... how much longer I don't know, but as long as it's not to the point where the moisture in the buds is literally freezing you shouldn't have any major problems. Just keep a close eye on them like you would under normal temperatures.