In the winter, it seems that whatever I do, my rear derailleur stops functioning after few weeks of commuting in light snow. Ice always gets in there somehow, and the chain refuses to move the wheel, ...
There is a lot of snow in the winter where I live. Different kinds of snow; soft, sticky, wet, etc. And ice too. It can get pretty cold: -25 °C (-15 °F). We drop salt, sand and gravel on our roads. ...