I don't know what I wrote that so upset
spandex but for the record...
Referring to that MTB ride of mine - I went out on NY Day precisely because it was a lovely sunny winter day. The sun was shining and I'd never ridden in snow before. Well, I really enjoyed riding in the snow though it did tend to clog the bike up somewhat. I was riding with caution but what can you do when you suddenly come across a 15% downhill slope with changing camber and bends and covered in a sheet of wet ice? Answer - fall off! I went down very hard and slid for about 30 metres it was that slippery. One benefit of falling off on ice, to be fair, is that road rash is minimal, but the risk of broken bones must be high!
Despite horror stories like
this , even I would never suggest not riding all winter. Perhaps the best advice is to keep your eye on local weather forecasts and steer clear of ungritted roads when there is a likelihood of frost. I do a lot of of my cycling on minor roads above 1,000 feet and they are lethal in very cold weather when the gritters don't get to them. If the road surface is below freezing, any rain falling can turn instantly to ice.