I was lucky to find some "hair ice" formations in near-freezing conditions in south Wales UK on 4 & 5 Jan 2019. These looked like snow from a distance, but it hadn't snowed, just cold nights down to about -2C.
It's also known as "cotton candy" or "candy-floss" ice, and according to reports on the internet require certain fungi to form. Growing on dead beech tree logs in this case.
Play my video
Another person's video of hair ice forming