Tundra-"a vast, flat, treeless Arctic region of Europe, Asia, and North America in which the subsoil is permanently frozen 10 inches to 3 feet down so that trees can't grow there." frommerriam-webster.com  I think that Tundra's were created by extremely long periods of cold weather, and other places in the world do not experience this type of weather. Along with the cold weather because the ground is frozen a lot of plants cant grow in this reign of the world and because of this there is nothing to stop wind from gusting so it is even colder.  

This picture illustrates the "might night sun"

Tundra's are extremely cold most of the year because it is very far away from the equator. Because of the earths tilt many places in the Arctic Circle experience cold weather along with longer nights in the winter because the sun dosnt directly hit them.While the sun doesn't shine much during the winter, it shines on the entire region for part of the day from March to September.

As you can see it can get very cold in the Arctic Circle.

Because of the cold weather in the Arctic Circle it makes it very hard for people to live in this region of the world. Also many people like to see the sun and when it hides for some of the year people d not like this. Tundra's have stayed about the same for the last couple of generations. They have stayed the same because of how little people inhabit these kinds of areas. Because this reign of the world is not very livable many brave scientist make the journey up their to research.