In Canada's arctic, winter is the best driving season because every winter, ice roads are built over frozen rivers and lakes, connecting communities that are usually accessible only by air.
Ice is surprisingly strong and forms early in the arctic. By December, it can support light trucks, and by January, the ice is more than a yard thick, allowing full size transport trucks to deliver fuel, food and other goods more easily and cheaply than aircraft. This means that many things are cheaper in the arctic in the dead of winter because they don't have to be flown in.
But ice roads are more than just frozen rivers. Road crews improve the ice road by taking advantage of the fact that ice floats. They drill holes in the ice and drive light trucks over them. The floating ice gives a little under the weight of the truck and forces water up through the holes where it spreads out to form a thin layer. This water then freezes and thickens the ice road. Road crews also maintain the road by plowing regularly, since open ice freezes more solidly than snow-covered ice.
Although ice roads are plowed like regular roads, they offer a different driving experience. Because ice has give, a wave is created under it as the vehicle drives on top. Driving too fast can create a wave strong enough to crack the ice, especially as you approach the shore. In cases like these, the speed limit is about 10 miles per hour.
In May, the ice breaks up and is washed away into the sea. So, if you want to drive up to Aklavik or Tuktoyaktuk, to see the northern lights, you'd better plan on winter driving.