"But Jamie, what is the point of winter riding?" you might ask. "Why would I expose myself to the dangers and discomfort of the scary white stuff, when by all that is natural and sacred my motorcycle should be peacefully sleeping in my heated garage?" you might also ask.
Winter riding needn't be either unpleasant, or unsafe - especially with a sidecar. With a two wheeled motorcyle you stand a strong risk (depending on tires, road conditions, etc) of hitting a patch of ice unexpectedly and then through a brief period of sky, ground, sky, ground, scream, thud, moan. (Which may not seem terribly brief while experiencing it.)
3 wheels will keep you upright, and as long as you give extra space and are aware of traction limits - you should be safe enough riding around in the snowy wonderland that is Canada in winter.
One disclaimer I should give is that I'm a Toronto rider, so for the most part I do get clear roads in winter. Also, my personal limits would be about -20C - the bike gets a bit more difficult to start up below that.
First things first: Get yourself warm gear.
First rule of winter riding gear is you need to block the wind and cover your skin. This will mean things like a windproof/water resistant suit, balaclava that covers the neck, warm gloves, etc.
For a suit, I recommend personally a one piece suit - personally I use the Firstgear Thermo which is an insulated rainsuit. It does an excellent job of blocking both wind and rain and is a great outer layer. Snowmobile suits also can work quite well for this. Keep in mind what the suit is made for - snowmobile suits may not have any abrasion resistance, and may be subject to melting if accidentally put against a hot exhaust.
A suit like this works well - this is the Firstgear Thermo.
For balaclava - get something that will cover the neck. Occasionally when it gets close to -20, I'll add a balaclava and then add a second neck warmer on top of that. You have some big blood vessels that go through the neck, and you can lose a huge amount of heat if cold air gets to it - so make sure you get that covered.
Gloves - personally I have a couple solutions I use. Right now I am using ATV handlebar mitts (with a hole added for the mirrors on my machine) and thin gloves combined with heated grips. The handlebar mitts do a good job of keeping wind/snow/rain off of my hands, and the thin gloves allow for dexterity when handling the controls.
Something like this:
I've also in the past used snowmobile mitts - Canadian tire occasionally sells leather ones, and the all fingers together one piece design really helps in keeping hands warm. Seams are not your friend when it comes to winter riding gear, and the mitts leak less air. Plus keeping your fingers together helps in keeping them warm.
Snowmobile boots might be an idea - something that is windproof, warm, waterproof. Especially if you ride in the city where salt is prevalent and slush gets all over your feet - even up and above on the footpegs or floorboard.
Which brings us to....
Taking care of your machine in Winter Riding:
First of all, if you are in an area like me where salt is used, be aware of the effect it can have on your motorcycle. Salt causes rust on steel, and will put and eat away at aluminum parts as well. One solution is a winter beater bike - something you don't mind getting a bit rusty and beaten up by the elements. Which will happen when you ride in winter.... plastics crack more easily, crud gets frozen into the bike and scratches form, vinyl tends to rip when cold, etc etc.
A protective oil product can help - spraying it can help protect metal parts of your machine. I've used ACF-50 which is an anti-corrosion product used by the aviation industry and it does a really good job. Just make sure when spraying the oil to keep it off of your tires - traction is bad enough in winter, you don't need to add oil to the mix.
If you have a chain, clean and lube it - ideally after every ride. It will extend the life of your chain. (Though I admit, if you are a back yard parker like me, this may not really be an option every time.)
In an ideal world - you would thoroughly wash the bike after every ride but without an enclosed space with adequate drainage, this likely isn't a real option. In which case do a very thorough wash as soon as it warms up - and again after a couple of weeks.
Especially during Canadian springs it can be a while before all the salt leaves the roadway.
Consider using a battery tender. Motorcycle batteries are small, and the oil used in a bike gets thicker the colder it gets - making the bike harder to start. Also components like starters may have greater difficulty working in the cold, which when combined with a battery losing capacity due to cold means your bike may not start when you want it to.
A battery tender will keep the battery from losing charge (possibly preventing damage) and will make sure you have the charge.to get the motor spinning - it can take a lot of cranking the colder it gets.
General riding tips:
Keep in mind, when riding in winter, that even on supposedly dry and clean pavement you will have reduced traction. Your tires will be colder, resulting in less grip. Ice can hide on the road, resulting in less grip.
Give extra distance ahead of you, be cautious in your braking and steering, and be gentle on the brakes whenever possible.
Be even on the brakes as well - use both front and back brake together.
In addition - keep in mind the "Traction bank". You have a set amount of traction, which is reduced in winter. If you use part of this to steer, this reduces the amount you have to brake. (And vice versa.) Therefore if you are steering, you need to be careful with how much brake is applied.
Also, be aware of other drivers. Frequently car drivers will forget to allow extra braking distance.... which makes it important for you to. If you can avoid panic braking, you can hopefully avoid the driver behind you being unable to stop and hitting you from behind.
In general - be aware, be cautious, and ride it like you borrowed it from your extra picky grandmother.
Winter riding can allow you to scratch that motorcycling itch when all of your friends are still stuck looking at pictures of past rides and moping morosely on a couch in a terribly depressing rec room. Because in winter, all rec rooms are depressing if you are a real motorcyclist.
Just be aware of the limits of your body, the limits of traction, and the limits of awareness of the drivers around you - and you'll be able to be out riding when others refuse to. You'll be that guy who gets called a crazy bastard at winter meetups, and takes a certain perverse pride in it.
Because you're a rider - and even the forces of nature can't stop you.
Except lightning. I got nothing to keep you safe with that.
Oh and tornadoes. And tigers will probably mess you up.
Actually.... nature can stop you. Nevermind. But still, winter is yours!