And, in fact, the only exposed bit, my eyes, did feel cold, like a pair of steel bearings. We had also been warned that contact lenses could be a problem, in that they might freeze and shatter, leaving splinters of frozen plastic embedded in the eye ball. As it happened, since at -30c it was still relatively warm, shattering was uncommon. Apparently, when there's a real cold snap, say -60c, you need to be careful not only with contact lenses but also with spectacles, which can either shatter or simply become welded to the face - in some cases on a permanent basis.