I once went into Lapland in March with an Africa Twin, with studded tyres. It is a lot tougher task than riding under normal "summer" conditions, and you need to be able to keep warm, otherwise you cannot ride, and will also compromise your safety, because its much harder to handle the controls and keep focussed if your suffering from the cold. And unless youre adequately prepared, you WILL suffer from the cold, a lot.

You will need to be able to see well, too, and normal helmet visors will be full of mist almost all the time. Monitoring the changing weather conditions is also very important, to listen to the forecasts, and plan when is a good time to ride and when is probably not such a good time. The Africa Twin was way too heavy for winter riding, if I were to do it again, I´d look into some 125-250cc enduros, the lighter the better.

The choice of the tyre (tread pattern) and type and number of the studs is also important. Especially on wet snow, if tread pattern fills up with it immediately, theres virtually no traction, studs or not, and if you have long spikes, they might be good on trails, but if your going to ride tarmac, you cannot use them because they will wear out in an eyeblink. If I remember corect, I used a stud meant for cars, which only comes out some 1-2mm from the tyre. Even they wore quite quickly.

When it was snowing (a lot), that was probably the worst weather, because you couldnt really see anything (the snow blocked the visor, glasses etc) and also when that snow starts to cover the ice underneath, well thats a bit of a handful! Especially on a heavy bike, you need to be able to pick it up very quickly if you fall, cannot leave it lying on the road under bad visibility. Would be good to have a riding partner who can warn oncoming traffic if you go down.

All other types of winter weather were relatively ok, cold is just a matter of preparation. When it drops to something like under -10C, though, the amount of preparation needed will skyrocket. Humidity %, combined with temperature reading is also an important factor.