temperature, whether too hot or too cold, WILL harm them ... small variations shouldn't matter too much, but I'd be worried if the variation was a great one ... and while where you live, the ambient humidity is more favorable than a lot of places, remember that your furnace will remove a lot of humidity from the air in the house ... best idea, IMNSHO, is to put a tupperwareador together ... cheap solution and you're gonna be needing it anyway ...