Others may know this, but I thought I'd pass it along. The other day I came back from a trip with my femme things hidden behind the seat of the truck, waiting until the next day to sneak them back inside. In the middle of the night I had a horrible realization - it's January and about 5 degrees F outside! I was in a bit of a panic imagining my silicone forms (from TruKare) bursting and turning into boob-sicles. Not to worry, they were fine the next day even after 12 hours in freezing temps. Probably not recommended, but good to know.