If you plan to skijor in all types of weather, get the warmest boot you can, or add a pair of ski boot coveralls. Remember that adding dog power may generate extra wind chill, and that you may not move your feet as much as you do when skiing by yourself. Skijoring can be hard on poles, so you may want to emphasize strength and durability rather than light weight. These are usually wide, padded belts that include an attachment system at the front for hooking to a skijoring line. Some belts come with leg straps, a nice enhancement that prevents the belt from sliding up your back.
Some people use a climbing harness for skijoring.
Plastic components can become brittle in extreme cold, and some of the more lightweight plastic connecting pieces have been known to break under stress. Whether you use a quick-release or some other method, whatever you use should be easy to release when you have gloves or mittens on. There may be times you do not want to be permanently attached to your dog, whether or your safety or for the dog's. Some potential scenarios include falling through ice, encountering a moose, losing control or falling when going downhill, becoming involved in a dog fight, or becoming seriously tangled with another team. When going down steep hills, some skijorers take the line off their belt and simply hold it in their hands in case they need to release their dog in a hurry.