Pralines are that way. If you want the best, the weather has to be right. I don't know what the requirement is, but I would ask my mom to make them or sometimes she would just make them because everything was right. We always had them at least once a year growing up.
I think a lot of candy making is temperature / environment sensitive and way crazier than baking is. I've got a couple of cookbooks with praline recipes, but I've never made them. I don't think they're real difficult but like you said the weather has to be right.