Mine is hanging on the wall outside my kitchen window
I wrapped some lagging around it on the coldest part of the winter, didn't have a problem.
The ideal of course is to have it inside a building of some sort, but providing you protect the membranes from frost you are ok.
This becomes more important the further north you are, this winter we only had one morning cold enough to freeze the water on the pavement as I was cleaning, wasn't cold enough to freeze it on the glass though, thank god
Further North than Chepstow South wales and I'm sure that would be different.
And talking of the weather; Have I missed something? I could have sworn that summer comes before winter, have we skipped a season? I'm going out to work bundled up like an arctic explorer
Perhaps I'd better check the lagging on my membranes.....
Ian