I left mine out in the weather for a good six years. It is in a glass cough medicine bottle. During that time, it faced temps as low as 0 F. It didn't freeze--at all. No crystallization, no nothing. Remained liquid as far as I could tell. The bottle remained intact.
I wouldn't recommend doing the same though, simply because plastic containers or plastic tops will deteriorate quicky if exposed for prolonger periods of sunlight. UV radiation breaks plastics down. I just wouldn't worry too much if you forgot the bottle over a winter, or two...