Questions on growing fruit and cold temperatures

I am in Manjimup, in the Southern Forest. I have a rock melon plant growing very happily with three fruits on it that are about the size of tennis balls right now. The temperatures of course are soon going to be dropping. Is it possible that the fruits will continue to grow until they are ready for harvesting? We don’t really get freezing temps here but it does get cool at night as winter approaches. And would it help if I put the plant under cover at night?

I also have some cucumber plants with dozens of small cukes on them. I guess I have the same question, will they continue to grow or will it get too cool for them to mature?