Snow!

only if you're going too fast, take it easy, choose your line carefully, control your speed and snow shouldn't be a problem.

I'll bet that people in snow-covered American cities are laughing at our ineptly of riding on the snow.

Ice however. (Snow after a frost) Is impossible to navigate on a thin tyre.

Watched a couple of hybrids wipe out this morning.

Fine on my MTB. Still tried to stick to salted roads though.